Matrix data scatter and gather by row

ABSTRACT

Embodiments for gathering and scattering matrix data by row are disclosed. In an embodiment, a processor includes a storage matrix, a decoder, and execution circuitry. The decoder is to decode an instruction having a format including an opcode field to specify an opcode and a first operand field to specify a set of irregularly spaced memory locations. The execution circuitry is to, in response to the decoded instruction, calculate a set of addresses corresponding to the set of irregularly spaced memory locations and transfer a set of rows of data between the storage and the set of irregularly spaced memory locations.

FIELD OF INVENTION

The field of invention relates generally to computer processorarchitecture, and, more specifically, to processing matrix data.

BACKGROUND

Matrices are increasingly important in many computing tasks such asmachine learning and other bulk data processing. Deep Learning is aclass of machine learning algorithms. Deep learning architectures, suchas deep neural networks, have been applied to fields including computervision, speech recognition, natural language processing, audiorecognition, social network filtering, machine translation,bioinformatics, and drug design.

Inference and training, two tools used for deep learning, are tendingtowards low precision arithmetic. Maximizing throughput of deep learningalgorithms and computations may assist in meeting the needs of deeplearning processors, for example, those performing deep learning in adata center.

Matrix-matrix multiplication (a.k.a., GEMM or General MatrixMultiplication) is a common compute-heavy operation on today'sprocessors. Special hardware for matrix multiplication (e.g., GEMM) is agood option for improving the peak compute (and energy efficiency) ofcertain applications, such as deep learning. Some of these applications,including deep learning, may operate on input data elements withrelatively few bits without losing accuracy, as long as the outputelements have enough bits (i.e., more than the inputs).

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by way of example and notlimitation in the figures of the accompanying drawings, in which likereferences indicate similar elements and in which:

FIG. 1A illustrates an embodiment of configured tiles;

FIG. 1B illustrates an embodiment of configured tiles;

FIG. 2 illustrates several examples of matrix storage;

FIG. 3 illustrates an embodiment of a system utilizing a matrix (tile)operations accelerator;

FIGS. 4 and 5 show different embodiments of how memory is shared using amatrix operations accelerator;

FIG. 6 illustrates an embodiment of matrix multiply accumulate operationusing tiles (“TMMA”);

FIG. 7 illustrates an embodiment of a subset of the execution of aniteration of a chained fused multiply accumulate instruction;

FIG. 8 illustrates an embodiment of a subset of the execution of aniteration of a chained fused multiply accumulate instruction;

FIG. 9 illustrates an embodiment of a subset of the execution of aniteration of a chained fused multiply accumulate instruction;

FIG. 10 illustrates an embodiment of a subset of the execution of aniteration of chained fused multiply accumulate instruction;

FIG. 11 illustrates power-of-two sized SIMD implementations wherein theaccumulators use input sizes that are larger than the inputs to themultipliers according to an embodiment;

FIG. 12 illustrates an embodiment of a system utilizing matrixoperations circuitry;

FIG. 13 illustrates an embodiment of a processor core pipelinesupporting matrix operations using tiles;

FIG. 14 illustrates an embodiment of a processor core pipelinesupporting matrix operations using tiles;

FIG. 15 illustrates an example of a matrix expressed in row major formatand column major format;

FIG. 16 illustrates an example of usage of matrices (tiles);

FIG. 17 illustrates an embodiment a method of usage of matrices (tiles);

FIG. 18 illustrates support for configuration of the usage of tilesaccording to an embodiment;

FIG. 19 illustrates an embodiment of a description of the matrices(tiles) to be supported;

FIGS. 20(A)-(D) illustrate examples of register(s);

FIGS. 21A, 21B, and 21C are block diagrams illustrating execution of aTILETFM2RI instruction according to some embodiments;

FIG. 22A is a block diagrams illustrating execution of a TGATHERROWinstruction according to some embodiments;

FIG. 22B is a block diagrams illustrating execution of a TSCATTERROWinstruction according to some embodiments;

FIG. 23 illustrates an embodiment of a processor executing a flow toprocess a TGATHERROW or TSCATTERROW instruction;

FIG. 24 is a block diagram illustrating a format of a TGATHERROW orTSCATTERROW instruction according to some embodiments;

FIGS. 25A-25B are block diagrams illustrating a generic vector friendlyinstruction format and instruction templates thereof according toembodiments;

FIG. 25A is a block diagram illustrating a generic vector friendlyinstruction format and class A instruction templates thereof accordingto embodiments;

FIG. 25B is a block diagram illustrating the generic vector friendlyinstruction format and class B instruction templates thereof accordingto embodiments;

FIG. 26A is a block diagram illustrating an exemplary specific vectorfriendly instruction format according to embodiments;

FIG. 26B is a block diagram illustrating the fields of the specificvector friendly instruction format that make up the full opcode fieldaccording to one embodiment;

FIG. 26C is a block diagram illustrating the fields of the specificvector friendly instruction format that make up the register index fieldaccording to one embodiment;

FIG. 26D is a block diagram illustrating the fields of the specificvector friendly instruction format that make up the augmentationoperation field according to one embodiment;

FIG. 27 is a block diagram of a register architecture according to oneembodiment;

FIG. 28A is a block diagram illustrating both an exemplary in-orderpipeline and an exemplary register renaming, out-of-orderissue/execution pipeline according to embodiments;

FIG. 28B is a block diagram illustrating both an exemplary embodiment ofan in-order architecture core and an exemplary register renaming,out-of-order issue/execution architecture core to be included in aprocessor according to embodiments;

FIGS. 29A-B illustrate a block diagram of a more specific exemplaryin-order core architecture, which core would be one of several logicblocks (including other cores of the same type and/or different types)in a chip;

FIG. 29A is a block diagram of a single processor core, along with itsconnection to the on-die interconnect network and with its local subsetof the Level 2 (L2) cache, according to embodiments;

FIG. 29B is an expanded view of part of the processor core in FIG. 29Aaccording to embodiments;

FIG. 30 is a block diagram of a processor that may have more than onecore, may have an integrated memory controller, and may have integratedgraphics according to embodiments;

FIGS. 31-34 are block diagrams of exemplary computer architectures;

FIG. 31 shown a block diagram of a system in accordance with oneembodiment of the present invention;

FIG. 32 is a block diagram of a first more specific exemplary system inaccordance with an embodiment of the present invention;

FIG. 33 is a block diagram of a second more specific exemplary system inaccordance with an embodiment of the present invention;

FIG. 34 is a block diagram of a System-on-a-Chip (SoC) in accordancewith an embodiment of the present invention; and

FIG. 35 is a block diagram contrasting the use of a software instructionconverter to convert binary instructions in a source instruction set tobinary instructions in a target instruction set according toembodiments.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth.However, it is understood that embodiments may be practiced withoutthese specific details. In other instances, well-known circuits,structures, and techniques have not been shown in detail in order not toobscure the understanding of this description.

References in the specification to “one embodiment,” “an embodiment,”“an example embodiment,” etc., indicate that the embodiment describedmay include a particular feature, structure, or characteristic, butevery embodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it is submitted that it is within the knowledge of oneskilled in the art to affect such feature, structure, or characteristicin connection with other embodiments whether or not explicitlydescribed.

As used in this specification and the claims and unless otherwisespecified, the use of the ordinal adjectives “first,” “second,” “third,”etc. to describe an element merely indicates that a particular instanceof an element or different instances of like elements are being referredto, and is not intended to imply that the elements so described must bein a particular sequence, either temporally, spatially, in ranking, orin any other manner. Also, as used in descriptions of embodiments of theinvention, a “/” character between terms may mean that what is describedmay include or be implemented using, with, and/or according to the firstterm and/or the second term (and/or any other additional terms).

In many mainstream processors, handling matrices is a difficult and/orinstruction intensive task. For example, rows of a matrix could be putinto a plurality of packed data (e.g., SIMD or vector) registers andthen operated on individually. For example, an add two 8×2 matrices mayrequire a load or gather into four packed data registers depending upondata sizes. Then a first add of packed data registers corresponding to afirst row from each matrix is performed and a second add of packed dataregisters corresponding to a second row from each matrix is performed.Then the resulting packed data registers are scattered back to memory.While for small matrices this scenario may be acceptable, it is oftennot acceptable with larger matrices.

Discussion

Described herein are mechanisms to support matrix operations in computerhardware such as central processing units (CPUs), graphic processingunits (GPUs), and accelerators. The matrix operations utilize2-dimensional (2-D) data structures representing one or more packedregions of memory such as registers. Throughout this description, these2-D data structures are referred to as tiles. Note that a matrix may besmaller than a tile (use less than all of a tile) or utilize a pluralityof tiles (the matrix is larger than the size of any one tile).Throughout the description, matrix (tile) language is used to indicateoperations performed using tiles that impact a matrix; whether or notthat matrix is larger than any one tile is not typically relevant.Architectures, operations, instructions, data, etc. to support and/orotherwise related to the processing of matrix data may be referred to,among other possibilities, as matrix, tile, and tile matrix multiplyaccumulate (TMMA) architectures, operations, instructions, data, etc. Insome contexts, matrix and tile may be used interchangeably.

Each tile may be acted upon by different operations such as those thatare detailed herein and include, but are not limited to: matrix (tile)multiplication, tile add, tile subtract, tile diagonal, tile zero, tiletransform, tile dot product, tile broadcast, tile row broadcast, tilecolumn broadcast, tile multiplication, tile multiplication andaccumulation, tile move, etc. Additionally, support for operators suchas the use of a scale and/or bias may be used with these operations orin support of non-numeric applications in the future, for instance,OpenCL “local memory,” data compression/decompression, etc. Alsodescribed herein are instructions for loading and storing matrix (tile)data with datatype conversion.

Portions of storage (such as memory (non-volatile and volatile),registers, cache, etc.) are arranged into tiles of different horizontaland vertical dimensions. For example, a tile may have horizontaldimension of 4 (e.g., four rows of a matrix) and a vertical dimension of8 (e.g., 8 columns of the matrix). Typically, the horizontal dimensionis related to element sizes (e.g., 2-, 4-, 8-, 16-, 32-, 64-, 128-bit,etc.). Multiple datatypes (single precision floating point, doubleprecision floating point, integer, etc.) may be supported.

Exemplary Usage of Configured Tiles

In some embodiments, tile parameters may be configured. For example, agiven tile may be configured to provide tile options. Exemplary tileoptions include but are not limited to: a number of rows of the tile, anumber of columns of the tile, whether the tile is VALID, and whetherthe tile consists of a PAIR of equal-sized tiles.

FIG. 1A illustrates an embodiment of configured tiles. As shown, 4 kB ofapplication memory 102 have stored thereon 4 1 kB titles, tile t0 104,tile t1 106, tile t2 108, and tile t3 110. In this example, the 4 tilesdo not consist of pairs, and each have elements arranged in rows andcolumns. Tile t0 104 and tile t1 106 have K rows and N columns of 4-byteelements (e.g., single precision data), where K equals 8 and N=32. Tilet2 108 and tile t3 110 have K rows and N/2 columns of 8-byte elements(e.g., double precision data). As the double precision operands aretwice the width of single precision, this configuration is consistentwith a palette, used to provide tile options, supplying at least 4 nameswith total storage of at least 4 kB. In operation, the tiles may beloaded from and stored to memory using load and store operations.Depending upon the instruction encoding scheme used, the amount ofavailable application memory, as well as the size, number, andconfiguration of available tiles varies.

FIG. 1B illustrates an embodiment of configured tiles. As shown, 4 kB ofapplication memory 122 have stored thereon 2 pairs of 1 kB-titles, thefirst pair being tile t4L 124 and tile t4R 126, and the second pairbeing tile t5L 128 and tile t5R 130. As shown the pairs of tiles aredivided into a left tile and a right tile. In other embodiments, thepair of tiles are divided into an even tile and an odd tile. In thisexample, the 4 tiles each have elements arranged in rows and columns.Tile t4L 124 and tile t4R 126 have K rows and N columns of 4-byteelements (e.g., single precision floating point data), where K equals 8and N equals 32. Tile t5L 128 and tile t5R 130 have K rows and N/2columns of 8-byte elements (e.g., double precision floating point data).As the double precision operands are twice the width of singleprecision, this configuration is consistent with a palette, used toprovide tile options, supplying at least 2 names with total storage ofat least 4 kB. The four tiles of FIG. 1A use 4 names, each naming a 1 kBtile, whereas the 2 pairs of tiles in FIG. 1B may use 2 names to specifythe paired tiles. In some embodiments, tile instructions accept a nameof a paired tile as an operand. In operation, the tiles may be loadedfrom and stored to memory using load and store operations. Dependingupon the instruction encoding scheme used, the amount of availableapplication memory, as well as the size, number, and configuration ofavailable tiles varies.

In some embodiments, tile parameters are definable. For example, a“palette” is used to provide tile options. Exemplary options include,but are not limited to: the number of tile names, the number of bytes ina row of storage, the number of rows and columns in a tile, etc. Forexample, a maximum “height” (number of rows) of a tile may be definedas: Tile Max Rows=Architected Storage/(The Number of Palette Names*TheNumber of Bytes per row).

As such, an application may be written such that a fixed usage of nameswill be able to take advantage of different storage sizes acrossimplementations.

Configuration of tiles may be done using a tile configuration(“TILECONFIG”) instruction, where a particular tile usage is defined ina selected palette. This declaration includes the number of tile namesto be used, the requested number of rows and columns per name (tile),and, in some embodiments, the requested datatype of each tile. In someembodiments, consistency checks are performed during the execution of aTILECONFIG instruction to determine that it matches the restrictions ofthe palette entry.

Exemplary Tile Storage Types

FIG. 2 illustrates several examples of matrix storage. In (A), a tile isstored in memory. As shown, each “row” consists of four packed dataelements. To get to the next “row,” a stride value is used. Note thatrows may be consecutively stored in memory. Strided memory accessesallow for access of one row to the next when the tile storage does notmap the underlying memory array row width.

Tile loads from memory and stores to memory are typically stridedaccesses from the application memory to packed rows of data. ExemplaryTILELOAD and TILESTORE instructions, or other instruction references toapplication memory as a TILE operand in load-op instructions, are, insome embodiments, restartable to handle (up to) 2*rows of page faults,unmasked floating point exceptions, and/or interrupts per instruction.

In (B), a matrix is stored in a tile comprised of a plurality ofregisters such as packed data registers (single instruction, multipledata (SIMD) or vector registers). In this example, the tile is overlaidon three physical registers. Typically, consecutive registers are used,however, this need not be the case.

In (C), a matrix is stored in a tile in non-register storage accessibleto a fused multiple accumulate (FMA) circuit used in tile operations.This storage may be inside of an FMA, or adjacent to it. Additionally,in some embodiments, discussed below, the storage may be for a dataelement and not an entire row or tile.

The supported parameters for the TMMA architecture are reported viaCPUID. In some embodiments, the list of information includes a maximumheight and a maximum SIMD dimension. Configuring the TMMA architecturerequires specifying the dimensions for each tile, the element size foreach tile and the palette identifier. This configuration is done byexecuting the TILECONFIG instruction.

Successful execution of a TILECONFIG instruction enables subsequent TILEoperators. A TILERELEASEALL instruction clears the tile configurationand disables the TILE operations (until the next TILECONFIG instructionsexecutes). In some embodiments, XSAVE, XSTORE, etc. are used in contextswitching using tiles. In some embodiments, 2 XCRO bits are used inXSAVE, one for TILECONFIG metadata and one bit corresponding to actualtile payload data.

TILECONFIG not only configures the tile usage, but also sets a statevariable indicating that the program is in a region of code with tilesconfigured. An implementation may enumerate restrictions on otherinstructions that may be used with a tile region such as no usage of anexisting register set, etc.

Exiting a tile region is typically done with the TILERELEASEALLinstruction. It takes no parameters and swiftly invalidates all tiles(indicating that the data no longer needs any saving or restoring) andclears the internal state corresponding to being in a tile region.

In some embodiments, tile operations may zero any rows and any columnsbeyond the dimensions specified by the tile configuration. For example,tile operations may zero the data beyond the configured number ofcolumns (factoring in the size of the elements) as each row is written.For example, with 64-byte rows and a tile configured with 10 rows and 12columns, an operation writing FP32 elements would write each of thefirst 10 rows with 12*4 bytes with output/result data and zero theremaining 4*4 bytes in each row. Tile operations also fully zero anyrows after the first 10 configured rows. When using 1K tile with 64-byterows, there would be 16 rows, so in this example, the last 6 rows wouldalso be zeroed.

In some embodiments, a context restore instruction (e.g., XRSTOR), whenloading data, enforces that the data beyond the configured rows for atile may be maintained as zero. If there is no valid configuration, allrows are zeroed. XRSTOR of tile data may load garbage in the columnsbeyond those configured. It should not be possible for XRSTOR to clearbeyond the number of columns configured because there is not an elementwidth associated with the tile configuration.

Context save (e.g., XSAVE) exposes the entire TILE storage area whenwriting it to memory. If XRSTOR loaded garbage data into the rightmostpart of a tile, that data may be saved by XSAVE. XSAVE may write zerosfor rows beyond the number specified for each tile.

In some embodiments, tile instructions are restartable. The operationsthat access memory allow restart after page faults. The computationalinstructions that deal with floating point operations also allow forunmasked floating-point exceptions, with the masking of the exceptionscontrolled by a control and/or status register.

To support restarting instructions after these events, the instructionsstore information in the start registers detailed below.

Matrix (Tile) Operation Systems Exemplary Hardware Support

FIG. 3 illustrates an embodiment of a system utilizing a matrix (tile)operations accelerator. In this illustration, a hostprocessor/processing system 301 communicates commands 311 (e.g., matrixmanipulation operations such as arithmetic or matrix manipulationoperations, or load and store operations) to a matrix operationsaccelerator 307. However, this is shown this way for discussion purposesonly. As detailed later, this accelerator 307 may be a part of aprocessing core. Typically, commands 311 that are tile manipulationoperator instructions may refer to tiles as register-register(“reg-reg”) or register-memory (“reg-mem”) format. Other commands suchas TILESTORE, TILELOAD, TILECONFIG, etc., do not perform data operationson a tile. Commands may be decoded instructions (e.g., micro-ops) ormacro-instructions for the accelerator 307 to handle.

In this example, a coherent memory interface 303 is coupled to the hostprocessor/processing system 301 and matrix operations accelerator 307such that they may share memory. FIGS. 4 and 5 show differentembodiments of how memory is shared using a matrix operationsaccelerator. As shown in FIG. 4, the host processor 401 and matrixoperations accelerator circuitry 405 share the same memory 403. FIG. 5illustrates an embodiment where the host processor 501 and matrixoperations accelerator 505 do not share memory but may access eachother's memory. For example, processor 501 may access tile memory 507and utilize its host memory 503 as normal. Similarly, the matrixoperations accelerator 505 may access host memory 503, but moretypically uses its own memory 507. Note these memories may be ofdifferent types.

In some embodiments, tiles are supported using an overlay over physicalregisters. For example, a tile may utilize 16 1,024-bit registers, 32512-bit registers, etc. depending on the implementation. In someembodiments, the matrix operations utilize 2-dimensional (2-D) datastructures representing one or more packed regions of memory such asregisters. Throughout this description, these 2-D data structures arereferred to as tiles or tile registers.

In some embodiments, the matrix operations accelerator 307 includes aplurality of FMAs 309 coupled to data buffers 305 (in someimplementations, one or more of these buffers 305 are stored in the FMAsof the grid as shown). The data buffers 305 buffer tiles loaded frommemory and/or tiles to be stored to memory (e.g., using a tileload ortilestore instruction). Data buffers may be, for example, a plurality ofregisters. Typically, these FMAs are arranged as a grid of chained FMAs309 which are able to read and write tiles. In this example, the matrixoperations accelerator 307 is to perform a matrix multiply operationusing tiles T0, T1, and T2. At least one of the tiles may be housed inthe FMA grid 309. In some embodiments, all tiles in an operation arestored in the FMA grid 309. In other embodiments, only a subset isstored in the FMA grid 309. As shown, T1 is housed and T0 and T2 arenot. Note that A, B, and C refer to the matrices of these tiles whichmay or may not take up the entire space of the tile.

FIG. 6 illustrates an embodiment of matrix multiply accumulate operationusing tiles (“TMMA”).

The number of rows in the matrix (TILE A 601) matches the number ofserial (chained) FMAs comprising the computation's latency. Animplementation is free to recirculate on a grid of smaller height, butthe computation remains the same.

The source/destination vector comes from a tile of N rows (TILE C 605)and the grid of FMAs 611 performs N vector-matrix operations resultingin a complete instruction performing a matrix multiplication of tiles.Tile B 603 is the other vector source and supplies “broadcast” terms tothe FMAs in each stage.

In operation, in some embodiments, the elements of matrix B (stored in atile B 603) are spread across the rectangular grid of FMAs. Matrix B(stored in tile A 601) has its elements of a row transformed to match upwith the columnar dimension of the rectangular grid of FMAs. At each FMAin the grid, an element of A and B are multiplied and added to theincoming summand (from above in the Figure) and the outgoing sum ispassed to the next row of FMAs (or the final output).

The latency of a single step is proportional to K (row height of matrixB) and dependent TMMAs typically have enough source-destination rows(either in a single tile or across tile) to hide that latency. Animplementation may also split the SIMD (packed data element) dimension M(row height of matrix A) across time steps, but this simply changes theconstant that K is multiplied by. When a program specifies a smaller Kthan the maximum enumerated by the TMACC, an implementation is free toimplement this with “masking” or “early outs.”

The latency of an entire TMMA is proportional to N*K. The repeat rate isproportional to N. The number of MACs per TMMA instruction is N*K*M.

FIG. 7 illustrates an embodiment of a subset of the execution of aniteration of a chained fused multiply accumulate instruction. Inparticular, this illustrates execution circuitry of an iteration of onepacked data element position of the destination. In this embodiment, thechained fused multiply accumulate is operating on signed sources whereinthe accumulator is 2× the input data size.

A first signed source (source 1 701) and a second signed source (source2 703) each have four packed data elements. Each of these packed dataelements stores signed data such as floating-point data. A third signedsource (source 3 709) has two packed data elements, each of which storessigned data. The sizes of the first and second signed sources 701 and703 are half that of the third signed source (initial value or previousresult) 709. For example, the first and second signed sources 701 and703 could have 32-bit packed data elements (e.g., single precisionfloating point) while the third signed source 709 could have 64-bitpacked data elements (e.g., double precision floating point).

In this illustration, only the two most significant packed data elementpositions of the first and second signed sources 701 and 703 and themost significant packed data element position of the third signed source709 are shown. Of course, the other packed data element positions wouldalso be processed.

As illustrated, packed data elements are processed in pairs. Forexample, the data of the most significant packed data element positionsof the first and second signed sources 701 and 703 are multiplied usinga multiplier circuit 705, and the data from second most significantpacked data element positions of the first and second signed sources 701and 703 are multiplied using a multiplier circuit 707. In someembodiments, these multiplier circuits 705 and 707 are reused for otherpacked data elements positions. In other embodiments, additionalmultiplier circuits are used so that the packed data elements areprocessed in parallel. In some contexts, parallel execution is doneusing lanes that are the size of the signed third source 709. Theresults of each of the multiplications are added using additioncircuitry 711.

The result of the addition of the results of the multiplications isadded to the data from most significant packed data element position ofthe signed source 3 709 (using a different adder 713 or the same adder711).

Finally, the result of the second addition is either stored into thesigned destination 715 in a packed data element position thatcorresponds to the packed data element position used from the signedthird source 709 or passed on to the next iteration if there is one. Insome embodiments, a writemask is applied to this storage such that if acorresponding writemask (bit) is set, the storage happens, and, if notset, the storage does not happen.

FIG. 8 illustrates an embodiment of a subset of the execution of aniteration of a chained fused multiply accumulate instruction. Inparticular, this illustrates execution circuitry of an iteration of onepacked data element position of the destination. In this embodiment, thechained fused multiply accumulate is operating on signed sources whereinthe accumulator is 2× the input data size.

A first signed source (source 1 801) and a second signed source (source2 803) each have four packed data elements. Each of these packed dataelements stores signed data such as integer data. A third signed source(source 3 809) has two packed data elements, each of which stores signeddata. The sizes of the first and second signed sources 801 and 803 arehalf that of the third signed source 809. For example, the first andsecond signed sources 801 and 803 could have 32-bit packed data elements(e.g., single precision floating point) the third signed source 809could have 64-bit packed data elements (e.g., double precision floatingpoint).

In this illustration, only the two most significant packed data elementpositions of the first and second signed sources 801 and 803 and themost significant packed data element position of the third signed source809 are shown. Of course, the other packed data element positions wouldalso be processed.

As illustrated, packed data elements are processed in pairs. Forexample, the data of the most significant packed data element positionsof the first and second signed sources 801 and 803 are multiplied usinga multiplier circuit 805, and the data from second most significantpacked data element positions of the first and second signed sources 801and 803 are multiplied using a multiplier circuit 807. In someembodiments, these multiplier circuits 805 and 807 are reused for otherpacked data elements positions. In other embodiments, additionalmultiplier circuits are used so that the packed data elements areprocessed in parallel. In some contexts, parallel execution is doneusing lanes that are the size of the signed third source (initial valueor previous iteration result) 809. The results of each of themultiplications are added to the signed third source 809 usingaddition/saturation circuitry 813.

Addition/saturation (accumulator) circuitry 813 preserves a sign of anoperand when the addition results in a value that is too big. Inparticular, saturation evaluation occurs on the infinite precisionresult between the multi-way-add and the write to the destination ornext iteration. When the accumulator 813 is floating point and the inputterms are integer, the sum of products and the floating-pointaccumulator input value are turned into infinite precision values (fixedpoint numbers of hundreds of bits), the addition of the multiplicationresults and the third input is performed, and a single rounding to theactual accumulator type is performed.

Unsigned saturation means the output values are limited to a maximumunsigned number for that element width (all 1s). Signed saturation meansa value is limited to the be in the range between a minimum negativenumber and a max positive number for that element width (for bytes forexample, the range is from −128 (=−2{circumflex over ( )}7) to127(=2{circumflex over ( )}7−1)).

The result of the addition and saturation check is stored into thesigned result 815 in a packed data element position that corresponds tothe packed data element position used from the signed third source 809or passed on to the next iteration if there is one. In some embodiments,a writemask is applied to this storage such that if a correspondingwritemask (bit) is set, the storage happens, and, if not set, thestorage does not happen.

FIG. 9 illustrates an embodiment of a subset of the execution of aniteration of a chained fused multiply accumulate instruction. Inparticular, this illustrates execution circuitry of an iteration of onepacked data element position of the destination. In this embodiment, thechained fused multiply accumulate is operating on a signed source and anunsigned source wherein the accumulator is 4× the input data size.

A first signed source (source 1 901) and a second unsigned source(source 2 903) each have four packed data elements. Each of these packeddata elements has data such as floating point or integer data. A thirdsigned source (initial value or result 915) has a packed data element ofwhich stores signed data. The sizes of the first and second sources 901and 903 are a quarter of the third signed source 915. For example, thefirst and second sources 901 and 903 could have 16-bit packed dataelements (e.g., word) and the third signed source 915 could have 64-bitpacked data elements (e.g., double precision floating point or 64-bitinteger).

In this illustration, the four most significant packed data elementpositions of the first and second sources 901 and 903 and the mostsignificant packed data element position of the third signed source 915are shown. Of course, other packed data element positions would also beprocessed if there are any.

As illustrated, packed data elements are processed in quadruplets. Forexample, the data of the most significant packed data element positionsof the first and second sources 901 and 903 are multiplied using amultiplier circuit 905, data from second most significant packed dataelement positions of the first and second sources 901 and 903 aremultiplied using a multiplier circuit 907, data from third mostsignificant packed data element positions of the first and secondsources 901 and 903 are multiplied using a multiplier circuit 909, anddata from the least significant packed data element positions of thefirst and second sources 901 and 903 are multiplied using a multipliercircuit 911. In some embodiments, the signed packed data elements of thefirst source 901 are sign extended and the unsigned packed data elementsof the second source 903 are zero extended prior to the multiplications.

In some embodiments, these multiplier circuits 905-911 are reused forother packed data elements positions. In other embodiments, additionalmultiplier circuits are used so that the packed data elements areprocessed in parallel. In some contexts, parallel execution is doneusing lanes that are the size of the signed third source 915. Theresults of each of the multiplications are added using additioncircuitry 913.

The result of the addition of the results of the multiplications isadded to the data from most significant packed data element position ofthe signed source 3 915 (using a different adder 917 or the same adder913).

Finally, the result 919 of the second addition is either stored into thesigned destination in a packed data element position that corresponds tothe packed data element position used from the signed third source 915or passed to the next iteration. In some embodiments, a writemask isapplied to this storage such that if a corresponding writemask (bit) isset, the storage happens, and, if not set, the storage does not happen.

FIG. 10 illustrates an embodiment of a subset of the execution of aniteration of chained fused multiply accumulate instruction. Inparticular, this illustrates execution circuitry of an iteration of onepacked data element position of the destination. In this embodiment, thechained fused multiply accumulate is operating on a signed source and anunsigned source wherein the accumulator is 4× the input data size.

A first signed source 1001 and a second unsigned source 1003 each havefour packed data elements. Each of these packed data elements storesdata such as floating point or integer data. A third signed source 1015(initial or previous result) has a packed data element of which storessigned data. The sizes of the first and second sources are a quarter ofthe third signed source 1015 (initial or previous result). For example,the first and second sources could have 16-bit packed data elements(e.g., word) and the third signed source 1015 (initial or previousresult) could have 64-bit packed data elements (e.g., double precisionfloating point or 64-bit integer).

In this illustration, the four most significant packed data elementpositions of the first signed source 1001 and the second unsigned source1003 and the most significant packed data element position of the thirdsigned source 1015 are shown. Of course, other packed data elementpositions would also be processed if there are any.

As illustrated, packed data elements are processed in quadruplets. Forexample, the data of the most significant packed data element positionsof the first signed source 1001 and the second unsigned source 1003 aremultiplied using a multiplier circuit 1005, data from second mostsignificant packed data element positions of the first signed source1001 and the second unsigned source 1003 are multiplied using amultiplier circuit 1007, data from third most significant packed dataelement positions of the first signed source 1001 and the secondunsigned source 1003 are multiplied using a multiplier circuit 1009, anddata from the least significant packed data element positions of thefirst signed source 1001 and the second unsigned source 1003 aremultiplied using a multiplier circuit 1011. In some embodiments, thesigned packed data elements of the first signed source 1001 are signextended and the unsigned packed data elements of the second unsignedsource 1003 are zero extended prior to the multiplications.

In some embodiments, these multiplier circuits 1005-1011 are reused forother packed data elements positions. In other embodiments, additionalmultiplier circuits are used so that the packed data elements areprocessed in parallel. In some contexts, parallel execution is doneusing lanes that are the size of third signed source 1015 (initial orprevious result). The result of the addition of the results of themultiplications is added to the data from most significant packed dataelement position of third signed source 1015 (initial or previousresult) using adder/saturation 1013 circuitry.

Addition/saturation (accumulator) circuitry 1013 preserves a sign of anoperand when the addition results in a value that is too big or toosmall for signed saturation. In particular, saturation evaluation occurson the infinite precision result between the multi-way-add and the writeto the destination. When the accumulator 1013 is floating point and theinput terms are integer, the sum of products and the floating-pointaccumulator input value are turned into infinite precision values (fixedpoint numbers of hundreds of bits), the addition of the multiplicationresults and the third input is performed, and a single rounding to theactual accumulator type is performed.

The result 1019 of the addition and saturation check is stored into thesigned destination in a packed data element position that corresponds tothe packed data element position used from third signed source 1015(initial or previous result) or passed to the next iteration. In someembodiments, a writemask is applied to this storage such that if acorresponding writemask (bit) is set, the storage happens, and, if notset, the storage does not happen.

FIG. 11 illustrates power-of-two sized SIMD implementations wherein theaccumulators use input sizes that are larger than the inputs to themultipliers according to an embodiment. Note the source (to themultipliers) and accumulator values may be signed or unsigned values.For an accumulator having 2× input sizes (in other words, theaccumulator input value is twice the size of the packed data elementsizes of the sources), table 1101 illustrates different configurations.For byte sized sources, the accumulator uses word or half-precisionfloating-point (HPFP) values that are 16-bit in size. For word sizedsources, the accumulator uses 32-bit integer or single-precisionfloating-point (SPFP) values that are 32-bit in size. For SPFP or 32-bitinteger sized sources, the accumulator uses 64-intenger ordouble-precision floating-point (DPFP) values that are 64-bit in size.

For an accumulator having 4× input sizes (in other words, theaccumulator input value is four times the size of the packed dataelement sizes of the sources), table 1103 illustrates differentconfigurations. For byte sized sources, the accumulator uses 32-bitinteger or single-precision floating-point (SPFP) values that are 32-bitin size. For word sized sources, the accumulator uses 64-bit integer ordouble-precision floating-point (DPFP) values that are 64-bit in size insome embodiments.

For an accumulator having 8× input sizes (in other words, theaccumulator input value is eight times the size of the packed dataelement sizes of the sources), table 1105 illustrates a configuration.For byte sized sources, the accumulator uses 64-bit integer.

As hinted at earlier, matrix operations circuitry may be included in acore, or as an external accelerator. FIG. 12 illustrates an embodimentof a system utilizing matrix operations circuitry. In this illustration,multiple entities are coupled with a ring interconnect 1245.

A plurality of cores, core 0 1201, core 1 1203, core 2 1205, and core N1207 provide non-tile-based instruction support. In some embodiments,matrix operations circuitry 1251 is provided in a core 1203, and inother embodiments matrix operations circuitry 1211 and 1213 areaccessible on the ring interconnect 1245.

Additionally, one or more memory controllers 1223-1225 are provided tocommunicate with memory 1233 and 1231 on behalf of the cores and/ormatrix operations circuitry.

FIG. 13 illustrates an embodiment of a processor core pipelinesupporting matrix operations using tiles. Branch prediction and decodecircuitry 1303 performs branch predicting of instructions, decoding ofinstructions, and/or both from instructions stored in instructionstorage 1301. For example, instructions detailed herein may be stored ininstruction storage. In some implementations, separate circuitry is usedfor branch prediction and in some embodiments, at least someinstructions are decoded into one or more micro-operations, micro-codeentry points, microinstructions, other instructions, or other controlsignals using microcode 1305. The branch prediction and decode circuitry1303 may be implemented using various different mechanisms. Examples ofsuitable mechanisms include, but are not limited to, look-up tables,hardware implementations, programmable logic arrays (PLAs), microcoderead only memories (ROMs), etc.

The branch prediction and decode circuitry 1303 is coupled toallocate/rename 1307 circuitry which is coupled, in some embodiments, toscheduler circuitry 1309. In some embodiments, these circuits provideregister renaming, register allocation, and/or scheduling functionalityby performing one or more of: 1) renaming logical operand values tophysical operand values (e.g., a register alias table in someembodiments), 2) allocating status bits and flags to the decodedinstruction, and 3) scheduling the decoded instruction for execution onexecution circuitry out of an instruction pool (e.g., using areservation station in some embodiments).

The scheduler circuitry 1309 represents any number of differentschedulers, including reservations stations, central instruction window,etc. The scheduler circuitry 1309 is coupled to, or includes, physicalregister file(s) 1315. Each of the physical register file(s) 1315represents one or more physical register files, different ones of whichstore one or more different data types, such as scalar integer, scalarfloating point, packed integer, packed floating point, vector integer,vector floating point, status (e.g., an instruction pointer that is theaddress of the next instruction to be executed), tiles, etc. In oneembodiment, the physical register file(s) 1315 comprises vectorregisters circuitry, write mask registers circuitry, and scalarregisters circuitry. These register circuits may provide architecturalvector registers, vector mask registers, and general-purpose registers.The physical register file(s) 1315 is overlapped by a retirement circuit1317 to illustrate various ways in which register renaming andout-of-order execution may be implemented (e.g., using a reorderbuffer(s) and a retirement register file(s); using a future file(s), ahistory buffer(s), and a retirement register file(s); using a registermaps and a pool of registers; etc.). The retirement circuit 1317 and thephysical register file(s) 1315 are coupled to the execution circuitry1311.

While register renaming is described in the context of out-of-orderexecution, it should be understood that register renaming may be used inan in-order architecture. While the illustrated embodiment of theprocessor may also include separate instruction and data cache units anda shared L2 cache unit, alternative embodiments may have a singleinternal cache for both instructions and data, such as, for example, aLevel 1 (L1) internal cache, or multiple levels of internal cache. Insome embodiments, the system may include a combination of an internalcache and an external cache that is external to the core and/or theprocessor. Alternatively, all of the cache may be external to the coreand/or the processor.

The execution circuitry 1311 is a set of one or more execution circuits,including scalar circuitry 1321, vector/SIMD circuitry 1323, and matrixoperations circuitry 1327, as well as memory access circuitry 1325 toaccess cache 1313. The execution circuits perform various operations(e.g., shifts, addition, subtraction, multiplication) and on varioustypes of data (e.g., scalar floating point, packed integer, packedfloating point, vector integer, vector floating point). While someembodiments may include a number of execution units dedicated tospecific functions or sets of functions, other embodiments may includeonly one execution unit or multiple execution units that all perform allfunctions. The scalar circuitry 1321 performs scalar operations, thevector/SIMD circuitry 1323 performs vector/SIMD operations, and matrixoperations circuitry 1327 performs matrix (tile) operations detailedherein.

By way of example, the exemplary register renaming, out-of-orderissue/execution core architecture may implement a pipeline asfollows: 1) an instruction fetch circuit performs fetch and lengthdecoding stages; 2) the branch and decode circuitry 1303 performs adecode stage; 3) the allocate/rename 1307 circuitry performs anallocation stage and renaming stage; 4) the scheduler circuitry 1309performs a schedule stage; 5) physical register file(s) (coupled to, orincluded in, the scheduler circuitry 1309 and allocate/rename 1307circuitry and a memory unit perform a register read/memory read stage;the execution circuitry 1311 performs an execute stage; 6) a memory unitand the physical register file(s) unit(s) perform a write back/memorywrite stage; 7) various units may be involved in the exception handlingstage; and 8) a retirement unit and the physical register file(s)unit(s) perform a commit stage.

The core may support one or more instructions sets (e.g., the x86instruction set (with some extensions that have been added with newerversions); the MIPS instruction set of MIPS Technologies of Sunnyvale,Calif.; the ARM instruction set (with optional additional extensionssuch as NEON) of ARM Holdings of Sunnyvale, Calif.), including theinstruction(s) described herein. In one embodiment, the core 1390includes logic to support a packed data instruction set extension (e.g.,AVX1, AVX2), thereby allowing the operations used by many multimediaapplications to be performed using packed data.

It should be understood that the core may support multithreading(executing two or more parallel sets of operations or threads), and maydo so in a variety of ways including time sliced multithreading,simultaneous multithreading (where a single physical core provides alogical core for each of the threads that physical core issimultaneously multithreading), or a combination thereof (e.g., timesliced fetching and decoding and simultaneous multithreading thereaftersuch as in the Intel® Hyperthreading technology).

FIG. 14 illustrates an embodiment of a processor core pipelinesupporting matrix operations using tiles. Branch prediction and decodecircuitry 1403 performs branch predicting of instructions, decoding ofinstructions, and/or both from instructions stored in instructionstorage 1401. For example, instructions detailed herein may be stored ininstruction storage. In some implementations, separate circuitry is usedfor branch prediction and in some embodiments, at least someinstructions are decoded into one or more micro-operations, micro-codeentry points, microinstructions, other instructions, or other controlsignals using microcode 1405. The branch prediction and decode circuitry1403 may be implemented using various different mechanisms. Examples ofsuitable mechanisms include, but are not limited to, look-up tables,hardware implementations, programmable logic arrays (PLAs), microcoderead only memories (ROMs), etc.

The branch prediction and decode circuitry 1403 is coupled toallocate/rename 1407 circuitry which is coupled, in some embodiments, toscheduler circuitry 1409. In some embodiments, these circuits provideregister renaming, register allocation, and/or scheduling functionalityby performing one or more of: 1) renaming logical operand values tophysical operand values (e.g., a register alias table in someembodiments), 2) allocating status bits and flags to the decodedinstruction, and 3) scheduling the decoded instruction for execution onexecution circuitry out of an instruction pool (e.g., using areservation station in some embodiments).

The scheduler circuitry 1409 represents any number of differentschedulers, including reservations stations, central instruction window,etc. The scheduler unit(s) scheduler circuitry 1409 is coupled to, orincludes, physical register file(s) 1415. Each of the physical registerfile(s) 1415 represents one or more physical register files, differentones of which store one or more different data types, such as scalarinteger, scalar floating point, packed integer, packed floating point,vector integer, vector floating point, status (e.g., an instructionpointer that is the address of the next instruction to be executed),tiles, etc. In one embodiment, the physical register file(s) 1415comprises vector registers circuitry, write mask registers circuitry,and scalar registers circuitry. These register circuits may providearchitectural vector registers, vector mask registers, andgeneral-purpose registers. The physical register file(s) 1415 isoverlapped by a retirement circuit 1417 to illustrate various ways inwhich register renaming and out-of-order execution may be implemented(e.g., using a reorder buffer(s) and a retirement register file(s);using a future file(s), a history buffer(s), and a retirement registerfile(s); using a register maps and a pool of registers; etc.). Theretirement circuit 1417 and the physical register file(s) 1415 arecoupled to the execution circuitry 1411.

While register renaming is described in the context of out-of-orderexecution, it should be understood that register renaming may be used inan in-order architecture. While the illustrated embodiment of theprocessor may also include separate instruction and data cache units anda shared L2 cache unit, alternative embodiments may have a singleinternal cache for both instructions and data, such as, for example, aLevel 1 (L1) internal cache, or multiple levels of internal cache. Insome embodiments, the system may include a combination of an internalcache and an external cache that is external to the core and/or theprocessor. Alternatively, all of the cache may be external to the coreand/or the processor.

The execution circuitry 1411 a set of one or more execution circuits1427 and a set of one or more memory access circuits 1425 to accesscache 1413. The execution circuits 1427 perform matrix (tile) operationsdetailed herein.

By way of example, the exemplary register renaming, out-of-orderissue/execution core architecture may implement a pipeline asfollows: 1) an instruction fetch circuit performs fetch and lengthdecoding stages; 2) the branch and decode circuitry 1403 performs adecode stage; 3) the allocate/rename 1407 circuitry performs anallocation stage and renaming stage; 4) the scheduler circuitry 1409performs a schedule stage; 5) physical register file(s) (coupled to, orincluded in, the scheduler circuitry 1409 and allocate/rename 1407circuitry and a memory unit perform a register read/memory read stage;the execution circuitry 1411 performs an execute stage; 6) a memory unitand the physical register file(s) unit(s) perform a write back/memorywrite stage; 7) various units may be involved in the exception handlingstage; and 8) a retirement unit and the physical register file(s)unit(s) perform a commit stage.

The core may support one or more instructions sets (e.g., the x86instruction set (with some extensions that have been added with newerversions); the MIPS instruction set of MIPS Technologies of Sunnyvale,Calif.; the ARM instruction set (with optional additional extensionssuch as NEON) of ARM Holdings of Sunnyvale, Calif.), including theinstruction(s) described herein. In one embodiment, the core 1490includes logic to support a packed data instruction set extension (e.g.,AVX1, AVX2), thereby allowing the operations used by many multimediaapplications to be performed using packed data.

It should be understood that the core may support multithreading(executing two or more parallel sets of operations or threads), and maydo so in a variety of ways including time sliced multithreading,simultaneous multithreading (where a single physical core provides alogical core for each of the threads that physical core issimultaneously multithreading), or a combination thereof (e.g., timesliced fetching and decoding and simultaneous multithreading thereaftersuch as in the Intel® Hyperthreading technology).

Layout

Throughout this description, data is expressed using row major datalayout. Column major users should translate the terms according to theirorientation. FIG. 15 illustrates an example of a matrix expressed in rowmajor format and column major format. As shown, matrix A is a 2×3matrix. When this matrix is stored in row major format, the dataelements of a row are consecutive. When this matrix is stored in columnmajor format, the data elements of a column are consecutive. It is awell-known property of matrices that A^(T)*B^(T)=(BA)^(T), wheresuperscript T means transform. Reading column major data as row majordata results in the matrix looking like the transform matrix.

In some embodiments, row-major semantics are utilized in hardware, andcolumn major data is to swap the operand order with the result beingtransforms of matrix, but for subsequent column-major reads from memoryit is the correct, non-transformed matrix.

For example, if there are two column-major matrices to multiply:

a b g i k ag+bh ai+bj ak+bl c d * h j l = cg+dh ci+dj ck+dl e f eg+fhei+fj ek+fl (3×2) (2×3) (3×3)

The input matrices would be stored in linear memory (column-major) as:

a c e b d fandg h i j k l.

Reading those matrices as row-major with dimensions 2×3 and 3×2, theywould appear as:

a c e and g h b d f i j k l

Swapping the order and matrix multiplying:

g h a c e ag+bh cg+dh eg+fh i j * b d f = ai+bj ci+dj ei+fj k l ak+blck+dl ek+fl

The transform matrix is out and may then be stored in in row-majororder:

ag+bh cg+dh eg+fh ai+bj ci+dj ei+fj ak+bl ck+dl ek+fland used in subsequent column major computations, it is the correctun-transformed matrix:

ag+bh ai+bj ak+bl cg+dh ci+dj ck+dl eg+fh ei+fj ek+fl

Exemplary Usage

FIG. 16 illustrates an example of usage of matrices (tiles). In thisexample, matrix C 1601 includes two tiles, matrix A 1603 includes onetile, and matrix B 1605 includes two tiles. This figure shows an exampleof the inner loop of an algorithm to compute a matrix multiplication. Inthis example, two result tiles, tmm0 and tmm1, from matrix C 1601 areused to accumulate the intermediate results. One tile from the matrix A1603 (tmm2) is reused twice as it multiplied by two tiles from matrix B1605. Pointers to load a new A matrix (tile) and two new B matrices(tiles) from the directions indicated by the arrows. An outer loop, notshown, adjusts the pointers for the C tiles.

The exemplary code as shown includes the usage of a tile configurationinstruction and is executed to configure tile usage, load tiles, a loopto process the tiles, store tiles to memory, and release tile usage.

FIG. 17 illustrates an embodiment of usage of matrices (tiles). At 1701,tile usage is configured. For example, a TILECONFIG instruction isexecuted to configure tile usage including setting a number of rows andcolumns per tile. Typically, at least one matrix (tile) is loaded frommemory at 1703. At least one matrix (tile) operation is performed at1705 using the matrices (tiles). At 1707, at least one matrix (tile) isstored out to memory and a context switch may occur at 1709.

Exemplary Configuration Tile Configuration Hardware Support

As discussed above, tile usage typically needs to be configured prior touse. For example, full usage of all rows and columns may not be needed.Not only does not configuring these rows and columns save power in someembodiments, but the configuration may be used to determine if anoperation will generate an error. For example, a matrix multiplicationof the form (N×M)*(L×N) typically not work if M and L are not the same.

Prior to using matrices using tiles, in some embodiments, tile supportis to be configured. For example, how many rows and columns per tile,tiles that are to be used, etc. are configured. A TILECONFIG instructionis an improvement to a computer itself as it provides for support toconfigure the computer to use a matrix accelerator (either as a part ofa processor core, or as an external device). In particular, an executionof the TILECONFIG instruction causes a configuration to be retrievedfrom memory and applied to matrix (tile) settings within a matrixaccelerator.

Tile Usage Configuration

FIG. 18 illustrates support for configuration of the usage of tilesaccording to an embodiment. A memory 1801 contains the tile description1803 of the matrices (tiles) to be supported.

Instruction execution resources 1811 of a processor/core 1805 storesaspects of a tile description 1803 into tile configurations 1817. Thetile configurations 1817 include palette table 1813 to detail what tilesfor a palette are configured (the number of rows and columns in eachtile) and a marking that matrix support is in use. In particular,instruction execution resources 1811 are configured to use tiles asspecified by the tile configurations 1817. The instruction executionresources 1811 may also include a machine specific register orconfiguration register to indicate tile usage. Additional values such asin-use and start values are also set. The tile configurations 1817utilize register(s) 1819 to store tile usage and configurationinformation.

FIG. 19 illustrates an embodiment of a description of the matrices(tiles) to be supported. This is the description that is to be storedupon an execution of a STTILECFG instruction. In this example, eachfield is a byte. In byte [0], a palette ID 1901 is stored. The paletteID is used to index a palette table 1813 which stores, per palette ID, anumber of bytes in a tile, and bytes per row of the tiles that areassociated with this ID as defined by the configuration.

Byte 1 stores a value to be stored in a “startRow” register 1903 andbyte 2 stores a value to be stored in a register, startP 1905. Tosupport restarting instructions after these events, the instructionsstore information these registers. To support restarting instructionsafter break events such as those detailed above, the instructions storeinformation in these registers. The startRow value indicates the rowthat should be used for restart. The startP value indicates the positionwithin the row for store operations when pairs are used and, in someembodiments, indicates the lower half of the row (in the lower tile of apair) or higher half of the row (in the higher tile of a pair).Generally, the position in the row (the column) is not needed.

With the exception of TILECONFIG and STTILECFG, successfully executingmatrix (tile) instructions may set both startRow and startP to zero.

Any time an interrupted matrix (tile) instruction is not restarted, itis the responsibility of software to zero the startRow and startPvalues. For example, unmasked floating point exception handlers mightdecide to finish the operation in software and change the programcounter value to another instruction, usually the next instruction. Inthis case the software exception handler must zero the startRow andstartP values in the exception presented to it by the operating systembefore resuming the program. The operating system may subsequentlyreload those values using a restore instruction.

Byte 3 stores an indication of pairs (lb per tile) of tiles 1907.

Bytes 16-17 store the number of rows 1913 and columns 1915 for tile 0,bytes 18-19 store the number of rows and columns for tile 1, etc. Inother words, each 2-byte group specifies a number of rows and columnsfor a tile. If a group of 2 bytes is not used to specify tileparameters, they should have the value zero. Specifying tile parametersfor more tiles than the implementation limit or the palette limitresults in a fault. Unconfigured tiles are set to an initial state with0 rows, 0 columns.

Finally, the configuration in memory typically ends with an endingdelineation such as all zeros for several consecutive bytes.

Exemplary Tile and Tile Configuration Storage

FIGS. 20(A)-(D) illustrate examples of register(s) 1819. FIG. 20(A)illustrates a plurality of registers 1819. As shown each tile (TMM0 2001. . . TMMN 2003) has a separate register with each register storing arow and column size for that particular tile. StartP 2011 and StartRow2013 are stored in separate registers. One or more status registers 2015are set (e.g., TILES_CONFIGURED=1) to indicate tiles are configured foruse.

FIG. 20(B) illustrates a plurality of registers 1819. As shown each tilehas separate registers for its rows and columns. For example, TMM0 rowsconfiguration 2021, TMM0 columns configuration 2023, StartP 2011 andStartRow 2013 are stored in separate registers. One or more statusregisters 2015 are set (e.g., TILES_CONFIGURED=1) to indicate tiles areconfigured for use.

FIG. 20(C) illustrates a single register 1819. As shown, this registerstores tile configurations (rows and columns per tile) 2031, StartP2011, and StartRow 2013 are stored in single register as packed dataregisters. One or more status registers 2015 are set (e.g.,TILES_CONFIGURED=1) to indicate tiles are configured for use.

FIG. 20(D) illustrates a plurality of registers 1819. As shown, a singleregister stores tile configuration (rows and columns per tile) 2031.StartP and StartRow are stored in separate registers 2011 and 2013. Oneor more status registers 2015 are set (e.g., TILES_CONFIGURED=1) toindicate tiles are configured for use.

Other combinations are contemplated such as combining the startregisters into a single register where they are shown separately, etc.

TILETFM2RI

As mentioned above, special hardware for General Matrix Multiplication(a.k.a., GEMM), is a good option for improving the peak compute (andenergy efficiency) of certain applications, such as deep learning. Someof these applications, including deep learning, can operate on inputdata elements with relatively few bits without losing accuracy, as longas the output elements have enough bits (i.e., more than the inputs).

Accordingly, disclosed methods and systems perform a transforminstruction, TILETFM2RI, that transforms a matrix (tile)—i.e., atwo-dimensional (2D) block of data—and writes its results into arow-interleaved (RowInt) formatted matrix/tile/2D register. Inparticular, a RowInt-formatted matrix can be used when performing fusedmultiply-add (FMA) operations (or other arithmetic) to perform the FMAand then combine (add together) the results of adjacent operations. Forexample, all of the element-wise multiplies specified by the vector ortile FMA can be performed, and then added together pairs of adjacentelements into accumulators being twice as large as the input values,which yields the same total number of bits in the output as in theinput. TILETFM2RI instructions enable such an optimization in a GEMMcontext.

Deep learning training (and possibly other applications) uses some tilesas both RowInt-formatted and regular-formatted. Thus, the applicationwill be sped up if a tile is transformed from a conventional 2D blockformat (i.e., with normal rows and columns) into RowInt format. TheRowInt format takes a group of consecutive rows of a matrix in “normal”format, and merges/interleaves those rows. In the context of GEMM-matrixmultiplication operations, what is ultimately needed is to multiply eachrow of matrix A with each column of matrix B. If B is in this RowIntformat, then in effect each column of matrix B is “shorter.”

FIG. 21A is a block diagram illustrating use of a TILETFM2RI instructionto accelerate matrix multiplication, according to some embodiments. Asshown, instruction 2101 includes an opcode 2102 (e.g. TILETFM2RI), whichindicates that the processor is to transform the specified source matrixinto the specified destination matrix having a row-interleaved (RowInt)format. In particular, in response to the opcode, the processor is tointerleave J elements of each J-element sub-column of the specifiedsource matrix in row-major order into a K-wide submatrix of thespecified destination matrix, the K-wide submatrix having K columns andenough rows to hold the J elements.

J 12108 and K 2110, which here equal four and two, are to be specifiedin one or more of several ways: as operands to the TILETFM2RIinstruction (as here), as suffixes or prefixes to the specified opcode,as part of an immediate provided with the instruction (e.g., J to bespecified by the lower 8 bits, and K to be specified by the upper 8 bitsof a 16-bit immediate), as part of control registers programmed bysoftware before issuing the instruction (e.g., XTILECONFIG), or even asarchitectural default values. J and K may each choose from an unlimitedrange of integer values.

Instruction 2101 further specifies destination matrix (tile) location2104 and source matrix (tile) location 2106. Each specified matrixlocations can be in any of a memory location, a collection of vectorregisters, and a collection of tile registers. Here, specified sourcematrix 2112 and destination matrix 2116 each includes thirty-two (32)word-sized elements. The specified source matrix 2112 includes four rowsand eight columns, while the specified destination matrix 2116 includes2 rows and 16 columns. As shown, specified destination matrix 2116 is arow-interleaved (RowInt) format transformation of the specified sourcematrix 2112.

Also shown is system 2100 for executing the TILETFM2RI instruction. Thesystem includes specified source matrix (tile) 2112, execution circuitry2114, and specified destination matrix (tile) 2116. Both the specifieddestination matrix (tile) 2116 and the specified source matrix in“normal” form 2112 are routed to matrix multiplication circuitry (GEMM)2118, improving GEMM performance and efficiency.

Alternate, inferior approaches to transforming matrix data may exist,but do not achieve the power and performance gains of the disclosedembodiments performing the TILETFM2RI instruction. In some otherapproaches, software can load data into vector/SIMD registers, performthe transform using vector instructions, write the reformatted data tomemory, and then load the reformatted data into a 2D/vector/tileregister. But doing the format transitions in vector instructions isslow, requires complex software tuning, and may require more space inthe cache.

Disclosed embodiments improve upon alternative approaches by allowingsoftware to perform the TILETFM2RI instruction to transformtwo-dimensional (2D) matrices (tiles) of data and place them intoRowInt-formatted 2D matrix (tile) registers. Advantageously, it isexpected to be simple for software to use this instruction, compared toapproaches limited to using vector registers.

In one embodiment, as further illustrated and described below withrespect to FIG. 21C, a processor is to perform a TILETFM2RI instructionto transform words from a pair of source matrices (tiles) and store theresult into a pair of destination matrices (tiles). TILETFM2RItransforms 2D tiles of data into so-called RowInt format and places theminto one or more 2D (i.e., tile) registers. In one embodiment, the lowernumbered tile of the source register pair represents the first 16 rowsof the tile pair, while the upper numbered tile of the source registerpair represents the next 16 rows of the tile pair. The first destinationtile will contain data from the first 16 columns of the source registerpair, while the second destination tile will contain data from thesecond 16 columns of the source register pair. In this embodiment, thesource tile (register-block) pair appears as upper/lower (which meansthe first tile holds rows 1-16 and the second tile holds rest of therows 17-32). The destination tile (register block) pair appears asleft/right (which means the first tile holds columns 1-16 and the secondtile holds rest of the columns 17-32).

Advantageously, disclosed embodiments can handle data elements of anysize (e.g., 1 byte, 2 bytes, 4 bytes). This includes sub-byte-sizedelements, such as 2-bit or 4-bit data elements.

As a further advantage, disclosed embodiments can also handle differentnumbers of input and output tiles, including a single tile, a pair, ormore than a pair.

The input data for this instruction may come from one or more tileregisters, from a set of vector registers, or from memory. Instructionsmay specify multiple tiles or vector registers as sources anddestinations and may explicitly encode each one. In some embodiments, onthe other hand, the instruction specifies the first register (forinstance, X), and the remaining registers are a fixed function of thatone (e.g., X+1, X+2, etc., or X+2, X+4, etc.). In some embodiments, aTILETFM2RI instruction specifies memory locations as locations of one ormore source or destination matrices (tiles).

When transforming rectangular tiles (with more rows than columns, orvice versa), a tile architecture may have an asymmetric limit on thenumber of rows and columns. Thus, some embodiments require more or fewerregisters to hold the input than the output.

In some embodiments, software is to add padding to an output tile (e.g.,to make the tile square), or remove it from an input tile. Disclosedembodiments allow for this. In some embodiments, the TILETFM2RIinstruction uses a parameter (e.g., in a register, as an immediate, oras part of the opcode) that indicates the number of elements to add toeach output row (or column) as padding. The value of a padded elementmay be zero, or some other pre-selected value, or this may be an inputto the instruction (as a register, an immediate, or part of the opcode).Alternatively, or additionally, the instruction may take a parameterindicating elements to remove from each input row or column and whetherthese are at the beginning, end, or some of each, of each row/column.

FIG. 21B illustrates an exemplary execution of a TILETFM2RI instructionaccording to some embodiments. As shown, instruction 2121 includes anopcode 2122 (e.g. TILETFM2RI), which indicates that the processor is totransform the specified source matrix into the specified destinationmatrix having a row-interleaved (RowInt) format. In particular, inresponse to the opcode, the processor is to interleave J elements ofeach J-element sub-column of the specified source matrix in row-majororder into a K-wide submatrix of the specified destination matrix, theK-wide submatrix having K columns and enough rows to hold the Jelements.

J 2128 and K 2130, which here equal four and two, are to be specified inone or more of several ways: as operands to the TILETFM2RI instruction(as here), as suffixes or prefixes to the specified opcode, as part ofan immediate provided with the instruction (e.g., J to be specified bythe lower 8 bits, and K to be specified by the upper 8 bits of a 16-bitimmediate), as part of control registers programmed by software beforeissuing the instruction (e.g., XTILECONFIG), or even as architecturaldefault values. J and K may each choose from an unlimited range ofinteger values.

Instruction 2121 further specifies destination matrix (tile) location2124 and source matrix (tile) location 2126. Each specified matrixlocations can be in any of a memory location, a collection of vectorregisters, and a collection of tile registers. Here, specified sourcematrix 2132 and destination matrix 2136 each includes thirty-two (32)word-sized elements. The specified source matrix 2132 includes four rowsand eight columns, while the specified destination matrix 2136 includes2 rows and 16 columns. As shown, specified destination matrix 2136 is arow-interleaved (RowInt) format transformation of the specified sourcematrix 2132.

Also shown is system 2120 for executing the TILETFM2RI instruction. Thesystem includes specified source matrix (tile) 2132, execution circuitry2134, and specified destination matrix (tile) 2136.

In operation, fetch and decode circuitry (not shown) are to fetch anddecode the TILETFM2RI instruction 2121. Execution circuitry 2136 is torespond to the decoded transform instruction by transforming thespecified source matrix into the specified RowInt-formatted destinationmatrix by interleaving J elements of each J-element sub-column of thespecified source matrix in row-major order into a K-wide submatrix ofthe specified destination matrix, the K-wide submatrix having K columnsand enough rows to hold the J elements.

FIG. 21C illustrates an exemplary execution of a TILETFM2RI instructionaccording to some embodiments. As shown, the format of instruction 2172includes fields to specify an opcode 2174 (e.g. TILETFM2RI) andlocations of destination matrix (tile) 2176, second destination matrix(tile) 2178, source matrix (tile) 2180, and second source matrix (tile)2182.

Instruction 2172 further specifies J 2184 and K 2186, which here areequal to four and two, respectively. It should be noted, however, that Jand K may be specified in one or more of several other ways: as operandsto the TILETFM2RI instruction, as suffixes or prefixes to the specifiedopcode, as part of an immediate provided with the instruction (e.g., Jto be specified by the lower 8 bits, and K to be specified by the upper8 bits of a 16-bit immediate), as part of control registers programmedby software before issuing the instruction (e.g., XTILECONFIG), or evenas architectural default values. J and K may each be set to an unlimitedrange of integer values.

Also shown is system 2170 for executing the TILETFM2RI instruction 2172.The system includes first specified source matrix (tile) 2188 and secondspecified source matrix (tile) 2195. System 2170 further includesexecution circuitry 2192 and specified first and second destinationmatrices (tiles) 2194 and 2196.

In operation, a processor is to perform a TILETFM2RI instruction 2172 totransform words from the pair of source matrices (tiles) and store theresult into the pair of destination matrices (tiles). TILETFM2RItransforms specified source 1 2184 and specified source 2 2186 matrices(tiles) into row-interleaved (RowInt) format and places them intospecified destination 1 and destination 2 2195 and 2192. In oneembodiment, as shown, the lower numbered tile of the source tile pairrepresents the first 16 rows of the tile pair, while the upper numberedtile of the source tile pair represents the next 16 rows of the tilepair. The first destination tile is to contain data from the first 16columns of the source tile pair, while the second destination tile is tocontain data from the second 16 columns of the source tile pair. In thisembodiment, the source tile (register-block) pair appears as upper/lower(which means the first tile holds rows 1-16 and the second tile holdsrest of the rows 17-32). The destination tile (register block) pairappears as left/right (which means the first tile holds columns 1-16 andthe second tile holds rest of the columns 17-32). In other embodiments,the destination tile (register block) pair appears as upper/lower.

In operation, fetch and decode circuitry, not shown, are to fetch anddecode the TILETFM2RI instruction 2172. Execution circuitry 2192 is torespond to the decoded matrix transform instruction by transforming thespecified source matrix into the specified RowInt-formatted destinationmatrix by interleaving J elements of each J-element sub-column of thespecified source matrix in row-major order into a K-wide submatrix ofthe specified destination matrix, the K-wide submatrix having K columnsand enough rows to hold the J elements. In other embodiments, the Jelements are to be interleaved into the K-wide submatrix in column-majororder.

Scatter and Gather by Row

As described above, tile loads from memory and stores to memory may beperformed with instructions such as TILELOAD and TILESTORE,respectively. Embodiments of the invention also provide for transferringdata into and out of rows of matrices (tiles) from and to arbitrary(irregularly spaced and/or not chosen/specified according to a stride orpattern) memory locations. Such embodiments may be desired to moreefficiently perform computations on matrix data that is not organized inmemory as a regular two-dimensional block, for sparse matrixmultiplication usages in which partial rows and columns of matrices arereordered, for usages in which only certain rows of a matrix are to beread or stored and others are to be padded with zeroes or other values,and for various other usages. Disclosed embodiments improve uponexisting approaches by allowing software to use one instance of a singleinstruction to perform a gather or scatter operation between arbitrary(irregularly spaced and/or not chosen/specified according to a stride orpattern) memory locations and rows of a matrix register.

For example, a single instruction, which may be referred to as aTSCATTERROW instruction or simply TSCATTERROW, may be used according toembodiments to scatter rows of a matrix (tile) to arbitrary (irregularlyspaced and/or not chosen/specified according to a stride or pattern)memory locations. Similarly, a single instruction, which may be referredto as a TGATHERROW instruction or simply TGATHERROW, may be usedaccording to embodiments to gather rows of a matrix (tile) fromarbitrary (irregularly spaced and/or not chosen/specified according to astride or pattern) memory locations. Embodiments may include any one ormore of a variety of types of TSCATTERROW and/or TGATHERROWinstructions, in addition to or instead of TILESTORE and/or TILELOADinstructions, to transfer matrix (tile) data to and from memory. Likethe TILESTORE and TILELOAD instructions described above, each suchTSCATTERROW, TGATHERROW, type of TSCATTERROW, and/or type of TGATHERROWinstruction may be restartable.

Any set or subset of these instructions (e.g., TSCATTERROW, TGATHERROW,type of TSCATTERROW, type of TGATHERROW) may be implemented in variousembodiments as entirely separate instructions (e.g., entirely separateopcodes to distinguish the operation (e.g., row scatter or gather) to beperformed and/or the size of the indices to be used to find the memorylocations of/for the matrix rows to be transferred, as described below),related instructions (e.g., sharing one or more bits of an opcode withone or more prefix, suffix, immediate, and/or other bit(s) todistinguish the operation/size), and/or leaves in a tree or hierarchy ofinstructions (e.g., the operation/size may be distinguished by contentof one or more registers and/or other storage when the instructionused), each as may be further described below. For example, theoperation/size for a TSCATTERROW and/or TGATHERROW instruction may bespecified by the opcode of the instruction; explicitly in one or moreprefixes or suffixes to the opcode; explicitly as one or more operandsor immediates of the instruction; explicitly in one or moreconfiguration or control registers (e.g., programmed by software priorto execution of the TSCATTERROW/TGATHERROW instruction); implicitly byone or more datatypes and/or sizes associated with one or moreregisters, memory ranges, or other storage; implicitly as one or morearchitectural default values; etc. Regardless of the implementation ofsuch sets or subsets, embodiments provide for an instruction setarchitecture (ISA) of an information processing system that allows aprogrammer or software developer to use a single instruction, ratherthan multiple instructions, to program the system to scatter and/orgather rows of matrices to and/or from arbitrary (e.g., irregularlyspaced and/or not chosen/specified according to a stride or pattern)memory locations.

For example, in embodiments, a processor or processor core may includean instruction unit and an execution unit, as shown in and described inconnection with the figures depicting processors and processor coresaccording to embodiments of the invention. The instruction unit mayinclude a decoder or other instruction hardware to decode or otherwisereceive instructions of an instruction set architecture that includes aone or more types of TSCATTERROW and/or TGATHERROW instructions, and inresponse to the decoder decoding and/or otherwise receiving an instanceof a TSCATTERROW or TGATHERROW instruction, hardware in and/orassociated with the execution unit (e.g., memory management and/orload/store hardware connected to an execution unit's arithmetic logicunit, etc.) may perform calculations (e.g., to determine memorylocations) and data transfer operations (e.g., to move data between theprocessor and system memory) to accomplish scattering or gathering ofrows of a matrix to/from the determined memory locations.

In embodiments, a decoder and execution hardware of a processor orprocessor core may be implemented to decode and execute one or moretypes of TSCATTERROW and/or TGATHERROW instructions; for example, afirst TGATHERROW instruction (e.g., TGATHERROWD) to gather matrix rowsfrom memory locations found using indices of a first size (e.g.,doubleword), a second TGATHERROW instruction (e.g., TGATHERROWQ) togather matrix rows from memory locations found using indices of a secondsize (e.g., quadword), a first TSCATTERROW instruction (e.g.,TSCATTERROWD) to scatter matrix rows to memory locations found usingindices of the first size (e.g., doubleword), and a second TSCATTERROWinstruction (e.g., TSCATTERROWQ) to scatter matrix rows from memorylocations found using indices of the second size (e.g., quadword).

In embodiments, tile rows may be gathered and scattered from/toarbitrary (irregularly spaced and/or not chosen/specified according to astride or pattern) memory locations by specifying (e.g., using one ormore operands of an instruction) a set of memory locations from/to whichto gather or scatter. For example, an instruction may have one or moreoperands to specify (e.g., according to ModRM/SIB address encoding, asdescribed below) a beginning memory address and a set of indices oroffsets, with which hardware according to embodiments may calculate aset of memory addresses (e.g., by adding each index value to thebeginning memory address, by adding each index value to a precedingmemory address in the set, etc.), from which hardware according toembodiments may load/store rows to/from a matrix (tile). The set ofindices may include any desired values (subject to index sizelimitations; various embodiments provide for various index sizes).Therefore, the set of memory locations from/to which matrix rows may beloaded/stored is not limited to being contiguous, being regularly spaced(e.g., as defined by a stride value), or by any other condition orpattern. In embodiments, the set of index values may be a vector, alist, an array, or other data structure, etc. of integer values storedin (e.g., prior to execution of a row scatter/gather instruction) and/orread from a memory location/range (e.g., a set of contiguous memorylocations specified by a beginning memory address) or one or moreregisters (e.g., integer, vector, or tile registers) indicated by anoperand of a row scatter/gather instruction.

In embodiments, a row scatter/gather instruction may (e.g., using one ormore bits of an opcode, prefix, suffix, immediate, hint field, etc., asrepresented by “[T1]” in the pseudocode below) allow the instruction tobe used (e.g., by a programmer) with an indication (the term “hint” maybe used to refer to the indication, the bit(s) usable to provide theindication, and/or a particular setting of the bit(s) that provides theindication) to the processor hardware that the data to be transferredshould bypass (i.e., not be cached in, if not already there) one (e.g.,a level one or L1 cache) or more cache memories in a memory hierarchybetween the source and the destination of the row scatter/gatherinstruction because the data is streaming data and/or not expected toused again (i.e., after the calculation/use for which it is beingtransferred by the row scatter/gather instruction) within a periodduring which the data, if cached, would be expected to be retained orotherwise remain in the cache (e.g., a performance benefit based onlocality, temporal or spatial, is not anticipated).

In an embodiment, a TGATHERROWD instruction may be executed to gathermatrix rows from memory locations found using indices of a first size(e.g., a doubleword). An embodiment may include hardware to perform thememory address calculations and the tile load operations (each of whichmay be performed as a memory read and a register write in a singleoperation or in two separate operations) as set forth in the followingpseudocode and as described below:

TGATHERROWD[T1] tdest, tsib2 membegin := tsib2.base + displacementtemp.dword[0 ... tdest.rows−1] := read_memory(tsib2.index, tdest.rows*4)start: tileconfig.startRow if start == 0: // not restarting, zeroincoming state tilezero tdest while start < tdest.rows: memptr :=membegin + SignExtend(temp.dword[start]) temp2.byte[0 ... tdest.colsb−1]:= read_memory(memptr, tdest.colsb) write_row_and_zero(tdest, start,temp2, tdest.colsb) start := start + 1 zero_upper_rows(tdest)zero_tileconfig_start( )

In an embodiment, a TGATHERROWQ instruction may be executed to gathermatrix rows from memory locations found using indices of a second size(e.g., a quadword). An embodiment may include hardware to perform thememory address calculations and the tile load operations (each of whichmay be performed as a memory read and a register write in a singleoperation or in two separate operations) as set forth in the followingpseudocode and as described below:

TGATHERROWQ[T1] tdest, tsib2 membegin := tsib2.base + displacementtemp.qword[0 ... tdest.rows−1] := read_memory(tsib2.index, tdest.rows*8)start := tileconfig.startRow if start == 0: // not restarting, zeroincoming state tilezero tdest while start < tdest.rows: memptr :=membegin + temp.qword[start] temp2.byte[0 ... tdest.colsb−1] :=read_memory(memptr, tdest.colsb) write_row_and_zero(tdest, start, temp2,tdest.colsb) start := start + 1 zero_upper_rows(tdest)zero_tileconfig_start( )

As may be seen from the pseudocode, a TGATHERROWD and/or TGATHERROWQinstruction may have a format in which a first operand specifies adestination location (e.g., tdest, which may represent an operand tospecify a tile register or other location for a tile) and a secondoperand specifies a set of source locations (e.g., tsib2, which mayrepresent an operand to specify a set of locations in a memory using aModRM byte, a SIB byte, and a displacement, each as described below),and execution of the instruction may include determining a beginningmemory address (e.g., by adding a displacement to a base addressspecified by a SIB byte) in a set of memory addresses, loading a rowfrom the beginning memory location (specified by the beginning memoryaddress) into the tile, and continuing to determine each remainingmemory address in the set (e.g., by adding, to the beginning memoryaddress, each of a set of index or offset values in a vector, list, etc.starting at a memory location in an index register specified by a SIBbyte) and loading rows from each remaining memory location (specified bythe remaining memory addresses) into the tile. In this example and otherembodiments, the scale field in the SIB byte is ignored (e.g., it has noeffect on address generation and there is no value in the scale fieldthat would trigger a fault).

FIG. 22A is a block diagram illustrating use of a row gather instructionto load matrix rows from arbitrary (irregularly spaced and/or notchosen/specified according to a stride or pattern) memory locations,according to some embodiments. As shown, instruction 2201 includes anopcode 2202 (e.g., TGATHERROW), which indicates that the processor is togather data from specified source locations and load it into rows of amatrix at the destination location. Instruction 2201 has a first operand2204 to specify a destination matrix (tile) location and a secondoperand 2206 to specify source locations (e.g., using a base,displacement, and index according to ModRM/SIB address encoding, asdescribed above and below) such that the source locations may beirregularly, arbitrarily, or flexibly spaced in memory. In other words,the source locations need not be contiguous or evenly spaced in memory.Therefore, embodiments provide for the source locations to be spaced inmemory unevenly and/or not according to a pattern (although inembodiments the source locations might all be aligned to a commonbyte-boundary, e.g., a 64-byte boundary in an embodiment in which thematrix row width is 64 bytes).

Also shown is system 2200 for executing the TGATHERROW instruction. Thesystem includes source locations 2216, 2217, 2218, and 2219, executioncircuitry 2220, and destination matrix (tile) 2214. Here, specifiedsource locations 2216, 2217, 2218, and 2219 are each 64-bytes wide tostore sixteen elements in FP32 format and are irregularly spaced inmemory, and destination matrix 2214 includes four 64-byte-wide rows andsixteen 32-bit-wide columns. Execution circuitry 2220 may includeaddress generation circuitry 2222 and load circuitry 2224.

In an embodiment, a TSCATTERROWD instruction may be executed to scattermatrix rows to memory locations found using indices of a first size(e.g., a doubleword). An embodiment may include hardware to perform thememory address calculations and the tile store operations (each of whichmay be performed as a register read and a memory write in a singleoperation or in two separate operations) as set forth in the followingpseudocode and as described below:

TSCATTERROWD[T1] tsib2, tsrc1 membegin := tsib2.base + displacementtemp.dword[0 ... tsrc1.rows−1] := read_memory(tsib2.index, tsrc1.rows*4)start := tileconfig.startRow while start < tdest.rows: memptr :=membegin + SignExtend(temp.dword[start]) write_memory(memptr,tsrc1.colsb, tsrc1.row[start]) start := start + 1 zero_tileconfig_start()

In an embodiment, a TSCATTERROWQ instruction may be executed to scattermatrix rows to memory locations found using indices of a second size(e.g., a quadword). An embodiment may include hardware to perform thememory address calculations and the tile store operations (each of whichmay be performed as a register read and a memory write in a singleoperation or in two separate operations) as set forth in the followingpseudocode and as described below:

TSCATTERROWQ[T1] tsib2, tsrc1 membegin := tsib2.base + displacementtemp.qword[0 ... tsrc1.rows−1] := read_memory(tsib2.index, tsrc1.rows*8)start := tileconfig.startRow while start < tdest.rows: memptr :=membegin + temp.qword[start] write_memory(memptr, tsrc1.colsb,tsrc1.row[start]) start := start + 1 zero_tileconfig_start( )

As may be seen from the pseudocode, a TSCATTERROWD and/or TSCATTERROWQinstruction may have a format in which a first operand specifies a setof destination locations (e.g., tsib2, which may represent an operand tospecify a set of locations in a memory using a ModRM byte, a SIB byte,and a displacement, each as described below) and a second operandspecifies a source location (e.g., tsrc1, which may represent an operandto specify a tile register or other location for a tile), and executionof the instruction may include determining a beginning memory address(e.g., by adding a displacement to a base address specified by a SIBbyte) in a set of memory addresses, storing a row from the tile to abeginning memory location (specified by the beginning memory address),and continuing to determine each remaining memory address in the set(e.g., by adding, to the beginning memory address, each of a set ofindex or offset values in a vector, list, etc. starting at a memorylocation in an index register specified by a SIB byte) and storing rowsfrom the tile into each remaining memory location (specified by theremaining memory addresses). In this example and other embodiments, thescale field in the SIB byte is ignored (e.g., it has no effect onaddress generation and there is no value in the scale field that wouldtrigger a fault).

FIG. 22B is a block diagram illustrating use of a row scatterinstruction to store matrix rows to arbitrary (e.g., irregularly spacedand/or not chosen/specified according to a stride or pattern) memorylocations, according to some embodiments. As shown, instruction 2251includes an opcode 2252 (e.g., TSCATTERROW), which indicates that theprocessor is to scatter rows from a matrix at the specified sourcelocation into specified memory locations. Instruction 2251 has a secondoperand 2256 to specify a source matrix (tile) location and a firstoperand 2254 to specify destination locations (e.g., using a base,displacement, and index according to ModRM/SIB address encoding, asdescribed above and below) such that the destination locations may beirregularly, arbitrarily, or flexibly spaced in memory. In other words,the destination locations need not be contiguous or evenly spaced inmemory. Therefore, embodiments provide for the destination locations tobe spaced in memory unevenly and/or not according to a pattern (althoughin embodiments the destination locations might all be aligned to acommon byte-boundary, e.g., a 64-byte boundary in an embodiment in whichthe matrix row width is 64 bytes).

Also shown is system 2250 for executing the TSCATTERROW instruction. Thesystem includes destination locations 2266, 2267, 2268, and 2269,execution circuitry 2270, and source matrix (tile) 2264. Here, specifieddestination locations 2266, 2267, 2268, and 2269 are each 64-bytes wideto store sixteen elements in FP32 format and are irregularly spaced inmemory, and source matrix 2264 includes four 64-byte-wide rows andsixteen 32-bit-wide columns. Execution circuitry 2270 may includeaddress generation circuitry 2272 and store circuitry 2274.

In some embodiments, a specific value for an index (e.g., MAXINT, or-MAXINT) may be reserved. For row scatters, when software specifies thatindex for a row, hardware will skip the write to memory. For rowgathers, when software specifies that index for a row, hardware willzero out that row rather than read anything from memory. This givessoftware a mechanism to easily pad tiles with some zero rows by using agather with a predetermined set of indices holding that special value,which may be desired instead of an approach in which software allocatesa row of zeros in memory and provide an index to it for the padded rows(which wastes memory and cache bandwidth).

In some embodiments, for row gather only, row gather functionality maybe combined with conversion to row-interleaved format (aka VNNIconversion), as described above. For example, a row gather instructionmay read two tiles of data from memory, rather than one, and performVNNI conversion on the tiles. In embodiments including hardware thatperforms matrix multiplication using a multiplicand tile in VNNI formatas an input, performance may be improved by using a row gatherinstruction with VNNI conversion to load a tile to use as an input formatrix multiplication.

Exemplary Method(s) of Execution

FIG. 23 illustrates an embodiment of a processor executing a flow 2300to process a TSCATTERROW or TGATHERROW instruction. As shown, at 2301,the processor is to fetch, using fetch circuitry, an instruction with aformat having fields to specify an opcode and locations of source anddestination rows of matrix data, wherein the opcode indicates that theprocessor is to read the data from the source rows and write it to thedestination rows. For a TSCATTERROW instruction, the source rows may bein a matrix (tile) register and the destination rows may be at arbitrary(irregularly spaced and/or not chosen/specified according to a stride orpattern) locations in a memory. For a TGATHERROW instruction, the sourcerows may be at arbitrary (e.g., irregularly spaced and/or notchosen/specified according to a stride or pattern) locations in a memoryand the destination rows may be in a matrix (tile) register.

At 2303, the processor is to decode, using decode circuitry, the fetchedinstruction. For example, the fetched TSCATTERROW or TGATHERROWinstruction is decoded by decode circuitry such as that detailed herein.In the context of the illustrated system, decode circuitry is similar tothat illustrated and described at least with respect to FIGS. 13, 14,and 28A-B.

Execution of the decoded instruction is scheduled (as needed) at 2305,which is optional (as indicated by its dashed border) insofar as it mayoccur at a different time, or not at all. At 2307, the processor is torespond, using execution circuitry, to the decoded instruction byperforming the calculations to generate the addresses of the arbitrarylocations of the destination rows for a TSCATTERROW instruction or ofthe source rows for a TGATHERROW instruction and storing, for aTSCATTERROW instruction, or loading, for a TGATHERROW instruction, thedata to/from memory.

Execution circuitry is further illustrated and described with respect toFIGS. 3-14. In some embodiments, execution circuitry includes a matrixoperations accelerator, such as that illustrated and described asaccelerator 307 (FIG. 3). In some embodiments, execution circuitryincludes a matrix operations circuit, such as matrix operationscircuitry 405 (FIG. 4), 505 (FIG. 5), or 1213 (FIG. 12), and 1327 (FIG.13).

Exemplary Instruction Format(s)

FIG. 24 is a block diagram illustrating a format of aTSCATTERROW/TGATHERROW instruction, according to some embodiments. Asshown, TSCATTERROW/TGATHERROW instruction 2400 includes fields forspecifying an opcode 2402, which indicates that the processor is to readthe data from source rows and write it to the destination rows.

Instruction 2400 further includes destination operand 2404 and sourceoperand 2406. For a TSCATTERROW instruction, the source operand mayspecify a matrix (tile) register and the destination operand may specifyarbitrary locations in a memory. For a TGATHERROW instruction, thesource operand may specify arbitrary locations in a memory and thedestination operand may specify a matrix (tile) register.

In some embodiments, one or more of optional instructions modifiers 2420(e.g., any parameters discussed above) are encoded in another operandand/or immediate field optionally included with the instruction 2400. Insome embodiments, one or more of optional instructions modifiers may bespecified via a configuration/status register (e.g., XTILECONFIG). Inother words, when any one or more of optional modifiers 2420 are notspecified by the instruction, they sometimes use implicit parametersthat are inherited from other parts of the tile architecture.

Detailed Exemplary Systems, Processors, and Emulation

Detailed herein are examples of hardware, software, etc. to execute theabove described instructions. For example, what is described belowdetails aspects of instruction execution including various pipelinestages such as fetch, decode, schedule, execute, retire, etc.

Instruction Sets

An instruction set may include one or more instruction formats. A giveninstruction format may define various fields (e.g., number of bits,location of bits) to specify, among other things, the operation to beperformed (e.g., opcode) and the operand(s) on which that operation isto be performed and/or other data field(s) (e.g., mask). Someinstruction formats are further broken down though the definition ofinstruction templates (or subformats). For example, the instructiontemplates of a given instruction format may be defined to have differentsubsets of the instruction format's fields (the included fields aretypically in the same order, but at least some have different bitpositions because there are less fields included) and/or defined to havea given field interpreted differently. Thus, each instruction of an ISAis expressed using a given instruction format (and, if defined, in agiven one of the instruction templates of that instruction format) andincludes fields for specifying the operation and the operands. Forexample, an exemplary ADD instruction has a specific opcode and aninstruction format that includes an opcode field to specify that opcodeand operand fields to select operands (source1/destination and source2);and an occurrence of this ADD instruction in an instruction stream mayhave specific contents in the operand fields that select specificoperands. A set of SIMD extensions referred to as the Advanced VectorExtensions (AVX) (AVX1 and AVX2) and using the Vector Extensions (VEX)coding scheme has been released and/or published (e.g., see Intel® 64and IA-32 Architectures Software Developer's Manual, September 2014; andsee Intel® Advanced Vector Extensions Programming Reference, October2014).

Exemplary Instruction Formats

Embodiments of the instruction(s) described herein may be embodied indifferent formats. Additionally, exemplary systems, architectures, andpipelines are detailed below. Embodiments of the instruction(s) may beexecuted on such systems, architectures, and pipelines, but are notlimited to those detailed.

Generic Vector Friendly Instruction Format

A vector friendly instruction format is an instruction format that issuited for vector instructions (e.g., there are certain fields specificto vector operations). While embodiments are described in which bothvector and scalar operations are supported through the vector friendlyinstruction format, alternative embodiments use only vector operationsthe vector friendly instruction format.

FIGS. 25A-25B are block diagrams illustrating a generic vector friendlyinstruction format and instruction templates thereof according toembodiments. FIG. 25A is a block diagram illustrating a generic vectorfriendly instruction format and class A instruction templates thereofaccording to embodiments; while FIG. 25B is a block diagram illustratingthe generic vector friendly instruction format and class B instructiontemplates thereof according to embodiments. Specifically, a genericvector friendly instruction format 2500 for which are defined class Aand class B instruction templates, both of which include no memoryaccess 2505 instruction templates and memory access 2520 instructiontemplates. The term generic in the context of the vector friendlyinstruction format refers to the instruction format not being tied toany specific instruction set.

While embodiments will be described in which the vector friendlyinstruction format supports the following: a 64 byte vector operandlength (or size) with 32 bit (4 byte) or 64 bit (8 byte) data elementwidths (or sizes) (and thus, a 64 byte vector consists of either 16doubleword-size elements or alternatively, 8 quadword-size elements); a64 byte vector operand length (or size) with 16 bit (2 byte) or 8 bit (1byte) data element widths (or sizes); a 32 byte vector operand length(or size) with 32 bit (4 byte), 64 bit (8 byte), 16 bit (2 byte), or 8bit (1 byte) data element widths (or sizes); and a 16 byte vectoroperand length (or size) with 32 bit (4 byte), 64 bit (8 byte), 16 bit(2 byte), or 8 bit (1 byte) data element widths (or sizes); alternativeembodiments may support more, less and/or different vector operand sizes(e.g., 256 byte vector operands) with more, less, or different dataelement widths (e.g., 128 bit (16 byte) data element widths).

The class A instruction templates in FIG. 25A include: 1) within the nomemory access 2505 instruction templates there is shown a no memoryaccess, full round control type operation 2510 instruction template anda no memory access, data transform type operation 2515 instructiontemplate; and 2) within the memory access 2520 instruction templatesthere is shown a memory access, temporal 2525 instruction template and amemory access, non-temporal 2530 instruction template. The class Binstruction templates in FIG. 25B include: 1) within the no memoryaccess 2505 instruction templates there is shown a no memory access,write mask control, partial round control type operation 2512instruction template and a no memory access, write mask control, vsizetype operation 2517 instruction template; and 2) within the memoryaccess 2520 instruction templates there is shown a memory access, writemask control 2527 instruction template.

The generic vector friendly instruction format 2500 includes thefollowing fields listed below in the order illustrated in FIGS. 25A-25B.

Format field 2540—a specific value (an instruction format identifiervalue) in this field uniquely identifies the vector friendly instructionformat, and thus occurrences of instructions in the vector friendlyinstruction format in instruction streams. As such, this field isoptional in the sense that it is not needed for an instruction set thathas only the generic vector friendly instruction format.

Base operation field 2542—its content distinguishes different baseoperations.

Register index field 2544—its content, directly or through addressgeneration, specifies the locations of the source and destinationoperands, be they in registers or in memory. These include a sufficientnumber of bits to select N registers from a P×Q (e.g. 32×512, 16×128,32×1024, 64×1024) register file. While in one embodiment N may be up tothree sources and one destination register, alternative embodiments maysupport more or less sources and destination registers (e.g., maysupport up to two sources where one of these sources also acts as thedestination, may support up to three sources where one of these sourcesalso acts as the destination, may support up to two sources and onedestination).

Modifier field 2546—its content distinguishes occurrences ofinstructions in the generic vector instruction format that specifymemory access from those that do not; that is, between no memory access2505 instruction templates and memory access 2520 instruction templates.Memory access operations read and/or write to the memory hierarchy (insome cases specifying the source and/or destination addresses usingvalues in registers), while non-memory access operations do not (e.g.,the source and destinations are registers). While in one embodiment thisfield also selects between three different ways to perform memoryaddress calculations, alternative embodiments may support more, less, ordifferent ways to perform memory address calculations.

Augmentation operation field 2550—its content distinguishes which one ofa variety of different operations to be performed in addition to thebase operation. This field is context specific. In one embodiment, thisfield is divided into a class field 2568, an alpha field 2552, and abeta field 2554. The augmentation operation field 2550 allows commongroups of operations to be performed in a single instruction rather than2, 3, or 4 instructions.

Scale field 2560—its content allows for the scaling of the index field'scontent for memory address generation (e.g., for address generation thatuses 2^(scale)*index+base).

Displacement Field 2562A—its content is used as part of memory addressgeneration (e.g., for address generation that uses2^(scale)*index+base+displacement).

Displacement Factor Field 2562B (note that the juxtaposition ofdisplacement field 2562A directly over displacement factor field 2562Bindicates one or the other is used)—its content is used as part ofaddress generation; it specifies a displacement factor that is to bescaled by the size of a memory access (N)—where N is the number of bytesin the memory access (e.g., for address generation that uses2^(scale)*index+base+scaled displacement). Redundant low-order bits areignored and hence, the displacement factor field's content is multipliedby the memory operands total size (N) in order to generate the finaldisplacement to be used in calculating an effective address. The valueof N is determined by the processor hardware at runtime based on thefull opcode field 2574 (described later herein) and the datamanipulation field 2554C. The displacement field 2562A and thedisplacement factor field 2562B are optional in the sense that they arenot used for the no memory access 2505 instruction templates and/ordifferent embodiments may implement only one or none of the two.

Data element width field 2564—its content distinguishes which one of anumber of data element widths is to be used (in some embodiments for allinstructions; in other embodiments for only some of the instructions).This field is optional in the sense that it is not needed if only onedata element width is supported and/or data element widths are supportedusing some aspect of the opcodes.

Write mask field 2570—its content controls, on a per data elementposition basis, whether that data element position in the destinationvector operand reflects the result of the base operation andaugmentation operation. Class A instruction templates supportmerging-writemasking, while class B instruction templates support bothmerging- and zeroing-writemasking. When merging, vector masks allow anyset of elements in the destination to be protected from updates duringthe execution of any operation (specified by the base operation and theaugmentation operation); in other one embodiment, preserving the oldvalue of each element of the destination where the corresponding maskbit has a 0. In contrast, when zeroing vector masks allow any set ofelements in the destination to be zeroed during the execution of anyoperation (specified by the base operation and the augmentationoperation); in one embodiment, an element of the destination is set to 0when the corresponding mask bit has a 0 value. A subset of thisfunctionality is the ability to control the vector length of theoperation being performed (that is, the span of elements being modified,from the first to the last one); however, it is not necessary that theelements that are modified be consecutive. Thus, the write mask field2570 allows for partial vector operations, including loads, stores,arithmetic, logical, etc. While embodiments are described in which thewrite mask field's 2570 content selects one of a number of write maskregisters that contains the write mask to be used (and thus the writemask field's 2570 content indirectly identifies that masking to beperformed), alternative embodiments instead or additional allow the maskwrite field's 2570 content to directly specify the masking to beperformed.

Immediate field 2572—its content allows for the specification of animmediate. This field is optional in the sense that it is not present inan implementation of the generic vector friendly format that does notsupport immediate and it is not present in instructions that do not usean immediate.

Class field 2568—its content distinguishes between different classes ofinstructions. With reference to FIGS. 25A-B, the contents of this fieldselect between class A and class B instructions. In FIGS. 25A-B, roundedcorner squares are used to indicate a specific value is present in afield (e.g., class A 2568A and class B 2568B for the class field 2568respectively in FIGS. 25A-B).

Instruction Templates of Class A

In the case of the non-memory access 2505 instruction templates of classA, the alpha field 2552 is interpreted as an RS field 2552A, whosecontent distinguishes which one of the different augmentation operationtypes are to be performed (e.g., round 2552A.1 and data transform2552A.2 are respectively specified for the no memory access, round typeoperation 2510 and the no memory access, data transform type operation2515 instruction templates), while the beta field 2554 distinguisheswhich of the operations of the specified type is to be performed. In theno memory access 2505 instruction templates, the scale field 2560, thedisplacement field 2562A, and the displacement scale filed 2562B are notpresent.

No-Memory Access Instruction Templates—Full Round Control Type Operation

In the no memory access full round control type operation 2510instruction template, the beta field 2554 is interpreted as a roundcontrol field 2554A, whose content(s) provide static rounding. While inthe described embodiments the round control field 2554A includes asuppress all floating-point exceptions (SAE) field 2556 and a roundoperation control field 2558, alternative embodiments may support mayencode both these concepts into the same field or only have one or theother of these concepts/fields (e.g., may have only the round operationcontrol field 2558).

SAE field 2556—its content distinguishes whether or not to disable theexception event reporting; when the SAE field's 2556 content indicatessuppression is enabled, a given instruction does not report any kind offloating-point exception flag and does not raise any floating-pointexception handler.

Round operation control field 2558—its content distinguishes which oneof a group of rounding operations to perform (e.g., Round-up,Round-down, Round-towards-zero and Round-to-nearest). Thus, the roundoperation control field 2558 allows for the changing of the roundingmode on a per instruction basis. In one embodiment where a processorincludes a control register for specifying rounding modes, the roundoperation control field's 2550 content overrides that register value.

No Memory Access Instruction Templates—Data Transform Type Operation

In the no memory access data transform type operation 2515 instructiontemplate, the beta field 2554 is interpreted as a data transform field2554B, whose content distinguishes which one of a number of datatransforms is to be performed (e.g., no data transform, swizzle,broadcast).

In the case of a memory access 2520 instruction template of class A, thealpha field 2552 is interpreted as an eviction hint field 2552B, whosecontent distinguishes which one of the eviction hints is to be used (inFIG. 25A, temporal 2552B.1 and non-temporal 2552B.2 are respectivelyspecified for the memory access, temporal 2525 instruction template andthe memory access, non-temporal 2530 instruction template), while thebeta field 2554 is interpreted as a data manipulation field 2554C, whosecontent distinguishes which one of a number of data manipulationoperations (also known as primitives) is to be performed (e.g., nomanipulation; broadcast; up conversion of a source; and down conversionof a destination). The memory access 2520 instruction templates includethe scale field 2560, and optionally the displacement field 2562A or thedisplacement scale field 2562B.

Vector memory instructions perform vector loads from and vector storesto memory, with conversion support. As with regular vector instructions,vector memory instructions transfer data from/to memory in a dataelement-wise fashion, with the elements that are actually transferred isdictated by the contents of the vector mask that is selected as thewrite mask.

Memory Access Instruction Templates—Temporal

Temporal data is data likely to be reused soon enough to benefit fromcaching. This is, however, a hint, and different processors mayimplement it in different ways, including ignoring the hint entirely.

Memory Access Instruction Templates—Non-Temporal

Non-temporal data is data unlikely to be reused soon enough to benefitfrom caching in the 1st-level cache and should be given priority foreviction. This is, however, a hint, and different processors mayimplement it in different ways, including ignoring the hint entirely.

Instruction Templates of Class B

In the case of the instruction templates of class B, the alpha field2552 is interpreted as a write mask control (Z) field 2552C, whosecontent distinguishes whether the write masking controlled by the writemask field 2570 should be a merging or a zeroing.

In the case of the non-memory access 2505 instruction templates of classB, part of the beta field 2554 is interpreted as an RL field 2557A,whose content distinguishes which one of the different augmentationoperation types are to be performed (e.g., round 2557A.1 and vectorlength (VSIZE) 2557A.2 are respectively specified for the no memoryaccess, write mask control, partial round control type operation 2512instruction template and the no memory access, write mask control, VSIZEtype operation 2517 instruction template), while the rest of the betafield 2554 distinguishes which of the operations of the specified typeis to be performed. In the no memory access 2505 instruction templates,the scale field 2560, the displacement field 2562A, and the displacementscale filed 2562B are not present.

In the no memory access, write mask control, partial round control typeoperation 2510 instruction template, the rest of the beta field 2554 isinterpreted as a round operation field 2559A and exception eventreporting is disabled (a given instruction does not report any kind offloating-point exception flag and does not raise any floating-pointexception handler).

Round operation control field 2559A—just as round operation controlfield 2558, its content distinguishes which one of a group of roundingoperations to perform (e.g., Round-up, Round-down, Round-towards-zeroand Round-to-nearest). Thus, the round operation control field 2559Aallows for the changing of the rounding mode on a per instruction basis.In one embodiment where a processor includes a control register forspecifying rounding modes, the round operation control field's 2550content overrides that register value.

In the no memory access, write mask control, VSIZE type operation 2517instruction template, the rest of the beta field 2554 is interpreted asa vector length field 2559B, whose content distinguishes which one of anumber of data vector lengths is to be performed on (e.g., 128, 256, or512 byte).

In the case of a memory access 2520 instruction template of class B,part of the beta field 2554 is interpreted as a broadcast field 2557B,whose content distinguishes whether or not the broadcast type datamanipulation operation is to be performed, while the rest of the betafield 2554 is interpreted the vector length field 2559B. The memoryaccess 2520 instruction templates include the scale field 2560, andoptionally the displacement field 2562A or the displacement scale field2562B.

With regard to the generic vector friendly instruction format 2500, afull opcode field 2574 is shown including the format field 2540, thebase operation field 2542, and the data element width field 2564. Whileone embodiment is shown where the full opcode field 2574 includes all ofthese fields, the full opcode field 2574 includes less than all of thesefields in embodiments that do not support all of them. The full opcodefield 2574 provides the operation code (opcode).

The augmentation operation field 2550, the data element width field2564, and the write mask field 2570 allow these features to be specifiedon a per instruction basis in the generic vector friendly instructionformat.

The combination of write mask field and data element width field createtyped instructions in that they allow the mask to be applied based ondifferent data element widths.

The various instruction templates found within class A and class B arebeneficial in different situations. In some embodiments, differentprocessors or different cores within a processor may support only classA, only class B, or both classes. For instance, a high performancegeneral purpose out-of-order core intended for general-purpose computingmay support only class B, a core intended primarily for graphics and/orscientific (throughput) computing may support only class A, and a coreintended for both may support both (of course, a core that has some mixof templates and instructions from both classes but not all templatesand instructions from both classes is within the purview of theinvention). Also, a single processor may include multiple cores, all ofwhich support the same class or in which different cores supportdifferent class. For instance, in a processor with separate graphics andgeneral-purpose cores, one of the graphics cores intended primarily forgraphics and/or scientific computing may support only class A, while oneor more of the general-purpose cores may be high performance generalpurpose cores with out of order execution and register renaming intendedfor general-purpose computing that support only class B. Anotherprocessor that does not have a separate graphics core, may include onemore general purpose in-order or out-of-order cores that support bothclass A and class B. Of course, features from one class may also beimplement in the other class in different embodiments. Programs writtenin a high level language would be put (e.g., just in time compiled orstatically compiled) into an variety of different executable forms,including: 1) a form having only instructions of the class(es) supportedby the target processor for execution; or 2) a form having alternativeroutines written using different combinations of the instructions of allclasses and having control flow code that selects the routines toexecute based on the instructions supported by the processor which iscurrently executing the code.

Exemplary Specific Vector Friendly Instruction Format

FIG. 26A is a block diagram illustrating an exemplary specific vectorfriendly instruction format according to embodiments. FIG. 26A shows aspecific vector friendly instruction format 2600 that is specific in thesense that it specifies the location, size, interpretation, and order ofthe fields, as well as values for some of those fields. The specificvector friendly instruction format 2600 may be used to extend the x86instruction set, and thus some of the fields are similar or the same asthose used in the existing x86 instruction set and extension thereof(e.g., AVX). This format remains consistent with the prefix encodingfield, real opcode byte field, MOD R/M field, SIB field, displacementfield, and immediate fields of the existing x86 instruction set withextensions. The fields from FIG. 25 into which the fields from FIG. 26Amap are illustrated.

It should be understood that, although embodiments are described withreference to the specific vector friendly instruction format 2600 in thecontext of the generic vector friendly instruction format 2500 forillustrative purposes, the invention is not limited to the specificvector friendly instruction format 2600 except where claimed. Forexample, the generic vector friendly instruction format 2500contemplates a variety of possible sizes for the various fields, whilethe specific vector friendly instruction format 2600 is shown as havingfields of specific sizes. By way of specific example, while the dataelement width field 2564 is illustrated as a one-bit field in thespecific vector friendly instruction format 2600, the invention is notso limited (that is, the generic vector friendly instruction format 2500contemplates other sizes of the data element width field 2564).

The generic vector friendly instruction format 2500 includes thefollowing fields listed below in the order illustrated in FIG. 26A.

EVEX Prefix 2602 (Bytes 0-3)—is encoded in a four-byte form.

Format Field 2540 (EVEX Byte 0, bits [7:0])—the first byte (EVEX Byte 0)is the format field 2540 and it contains 0x62 (the unique value used fordistinguishing the vector friendly instruction format in oneembodiment).

The second-fourth bytes (EVEX Bytes 1-3) include a number of bit fieldsproviding specific capability.

REX field 2605 (EVEX Byte 1, bits [7-5])—consists of a EVEX.R bit field(EVEX Byte 1, bit [7]—R), EVEX.X bit field (EVEX byte 1, bit [6]—X), and2557BEX byte 1, bit [5]—B). The EVEX.R, EVEX.X, and EVEX.B bit fieldsprovide the same functionality as the corresponding VEX bit fields, andare encoded using 1s complement form, i.e. ZMM0 is encoded as 1111B,ZMM15 is encoded as 0000B. Other fields of the instructions encode thelower three bits of the register indexes as is known in the art (rrr,xxx, and bbb), so that Rrrr, Xxxx, and Bbbb may be formed by addingEVEX.R, EVEX.X, and EVEX.B.

REX′ field 2510—this is the first part of the REX′ field 2510 and is theEVEX.R′ bit field (EVEX Byte 1, bit [4]—R′) that is used to encodeeither the upper 16 or lower 16 of the extended 32 register set. In oneembodiment, this bit, along with others as indicated below, is stored inbit inverted format to distinguish (in the well-known x86 32-bit mode)from the BOUND instruction, whose real opcode byte is 62, but does notaccept in the MOD R/M field (described below) the value of 11 in the MODfield; alternative embodiments do not store this and the other indicatedbits below in the inverted format. A value of 1 is used to encode thelower 16 registers. In other words, R′Rrrr is formed by combiningEVEX.R′, EVEX.R, and the other RRR from other fields.

Opcode map field 2615 (EVEX byte 1, bits [3:0]—mmmm)—its content encodesan implied leading opcode byte (0F, 0F 38, or 0F 3).

Data element width field 2564 (EVEX byte 2, bit [7]—W)—is represented bythe notation EVEX.W. EVEX.W is used to define the granularity (size) ofthe datatype (either 32-bit data elements or 64-bit data elements).

EVEX.vvvv 2620 (EVEX Byte 2, bits [6:3]-vvvv)—the role of EVEX.vvvv mayinclude the following: 1) EVEX.vvvv encodes the first source registeroperand, specified in inverted (1s complement) form and is valid forinstructions with 2 or more source operands; 2) EVEX.vvvv encodes thedestination register operand, specified in 1s complement form forcertain vector shifts; or 3) EVEX.vvvv does not encode any operand, thefield is reserved and should contain 1111b. Thus, EVEX.vvvv field 2620encodes the 4 low-order bits of the first source register specifierstored in inverted (1s complement) form. Depending on the instruction,an extra different EVEX bit field is used to extend the specifier sizeto 32 registers.

EVEX.U 2568 Class field (EVEX byte 2, bit [2]—U)—If EVEX.U=0, itindicates class A or EVEX.U0; if EVEX.U=1, it indicates class B orEVEX.U1.

Prefix encoding field 2625 (EVEX byte 2, bits [1:0]-pp)—providesadditional bits for the base operation field. In addition to providingsupport for the legacy SSE instructions in the EVEX prefix format, thisalso has the benefit of compacting the SIMD prefix (rather thanrequiring a byte to express the SIMD prefix, the EVEX prefix requiresonly 2 bits). In one embodiment, to support legacy SSE instructions thatuse a SIMD prefix (66H, F2H, F3H) in both the legacy format and in theEVEX prefix format, these legacy SIMD prefixes are encoded into the SIMDprefix encoding field; and at runtime are expanded into the legacy SIMDprefix prior to being provided to the decoder's PLA (so the PLA mayexecute both the legacy and EVEX format of these legacy instructionswithout modification). Although newer instructions could use the EVEXprefix encoding field's content directly as an opcode extension, certainembodiments expand in a similar fashion for consistency but allow fordifferent meanings to be specified by these legacy SIMD prefixes. Analternative embodiment may redesign the PLA to support the 2-bit SIMDprefix encodings, and thus not require the expansion.

Alpha field 2552 (EVEX byte 3, bit [7]—EH; also known as EVEX.EH,EVEX.rs, EVEX.RL, EVEX.write mask control, and EVEX.N; also illustratedwith α)—as previously described, this field is context specific.

Beta field 2554 (EVEX byte 3, bits [6:4]-SSS, also known as EVEX.s₂₋₀,EVEX.r₂₋₀, EVEX.rr1, EVEX.LL0, EVEX.LLB; also illustrated with βββ)—aspreviously described, this field is context specific.

REX′ field 2510—this is the remainder of the REX′ field and is theEVEX.V′ bit field (EVEX Byte 3, bit [3]—V′) that may be used to encodeeither the upper 16 or lower 16 of the extended 32 register set. Thisbit is stored in bit inverted format. A value of 1 is used to encode thelower 16 registers. In other words, V′VVVV is formed by combiningEVEX.V′, EVEX.vvvv.

Write mask field 2570 (EVEX byte 3, bits [2:0]-kkk)—its contentspecifies the index of a register in the write mask registers aspreviously described. In one embodiment, the specific value EVEX.kkk=000has a special behavior implying no write mask is used for the particularinstruction (this may be implemented in a variety of ways including theuse of a write mask hardwired to all ones or hardware that bypasses themasking hardware).

Real Opcode Field 2630 (Byte 4) is also known as the opcode byte. Partof the opcode is specified in this field.

MOD R/M Field 2640 (Byte 5) includes MOD field 2642, Reg field 2644, andR/M field 2646. As previously described, the MOD field's 2642 contentdistinguishes between memory access and non-memory access operations.The role of Reg field 2644 may be summarized to two situations: encodingeither the destination register operand or a source register operand orbe treated as an opcode extension and not used to encode any instructionoperand. The role of R/M field 2646 may include the following: encodingthe instruction operand that references a memory address or encodingeither the destination register operand or a source register operand.

Scale, Index, Base (SIB) Byte (Byte 6)—As previously described, thecontent of SIB 2650 is used for memory address generation. SIB.xxx 2654and SIB.bbb 2656—the contents of these fields have been previouslyreferred to with regard to the register indexes Xxxx and Bbbb.

Displacement field 2562A (Bytes 7-10)—when MOD field 2642 contains 10,bytes 7-10 are the displacement field 2562A, and it works the same asthe legacy 32-bit displacement (disp32) and works at byte granularity.

Displacement factor field 2562B (Byte 7)—when MOD field 2642 contains01, byte 7 is the displacement factor field 2562B. The location of thisfield is that same as that of the legacy x86 instruction set 8-bitdisplacement (disp8), which works at byte granularity. Since disp8 issign extended, it may only address between −128 and 127 bytes offsets;in terms of 64-byte cache lines, disp8 uses 8 bits that may be set toonly four really useful values −128, −64, 0, and 64; since a greaterrange is often needed, disp32 is used; however, disp32 requires 4 bytes.In contrast to disp8 and disp32, the displacement factor field 2562B isa reinterpretation of disp8; when using displacement factor field 2562B,the actual displacement is determined by the content of the displacementfactor field multiplied by the size of the memory operand access (N).This type of displacement is referred to as disp8*N. This reduces theaverage instruction length (a single byte of used for the displacementbut with a much greater range). Such compressed displacement assumesthat the effective displacement is multiple of the granularity of thememory access, and hence, the redundant low-order bits of the addressoffset do not need to be encoded. In other words, the displacementfactor field 2562B substitutes the legacy x86 instruction set 8-bitdisplacement. Thus, the displacement factor field 2562B is encoded thesame way as an x86 instruction set 8-bit displacement (so no changes inthe ModRM/SIB encoding rules) with the only exception that disp8 isoverloaded to disp8*N. In other words, there are no changes in theencoding rules or encoding lengths but only in the interpretation of thedisplacement value by hardware (which needs to scale the displacement bythe size of the memory operand to obtain a byte-wise address offset).Immediate field 2572 operates as previously described.

Full Opcode Field

FIG. 26B is a block diagram illustrating the fields of the specificvector friendly instruction format 2600 that make up the full opcodefield 2574 according to one embodiment. Specifically, the full opcodefield 2574 includes the format field 2540, the base operation field2542, and the data element width (W) field 2564. The base operationfield 2542 includes the prefix encoding field 2625, the opcode map field2615, and the real opcode field 2630.

Register Index Field

FIG. 26C is a block diagram illustrating the fields of the specificvector friendly instruction format 2600 that make up the register indexfield 2544 according to one embodiment. Specifically, the register indexfield 2544 includes the REX 2605 field, the REX′ 2610 field, theMODR/M.reg field 2644, the MODR/M.r/m field 2646, the VVVV field 2620,xxx field 2654, and the bbb field 2656.

Augmentation Operation Field

FIG. 26D is a block diagram illustrating the fields of the specificvector friendly instruction format 2600 that make up the augmentationoperation field 2550 according to one embodiment. When the class (U)field 2568 contains 0, it signifies EVEX.U0 (class A 2568A); when itcontains 1, it signifies EVEX.U1 (class B 2568B). When U=0 and the MODfield 2642 contains 11 (signifying a no memory access operation), thealpha field 2552 (EVEX byte 3, bit [7]—EH) is interpreted as the rsfield 2552A. When the rs field 2552A contains a 1 (round 2552A.1), thebeta field 2554 (EVEX byte 3, bits [6:4]—SSS) is interpreted as theround control field 2554A. The round control field 2554A includes aone-bit SAE field 2556 and a two-bit round operation field 2558. Whenthe rs field 2552A contains a 0 (data transform 2552A.2), the beta field2554 (EVEX byte 3, bits [6:4]—SSS) is interpreted as a three-bit datatransform field 2554B. When U=0 and the MOD field 2642 contains 00, 01,or 10 (signifying a memory access operation), the alpha field 2552 (EVEXbyte 3, bit [7]—EH) is interpreted as the eviction hint (EH) field 2552Band the beta field 2554 (EVEX byte 3, bits [6:4]—SSS) is interpreted asa three bit data manipulation field 2554C.

When U=1, the alpha field 2552 (EVEX byte 3, bit [7]—EH) is interpretedas the write mask control (Z) field 2552C. When U=1 and the MOD field2642 contains 11 (signifying a no memory access operation), part of thebeta field 2554 (EVEX byte 3, bit [4]—S₀) is interpreted as the RL field2557A; when it contains a 1 (round 2557A.1) the rest of the beta field2554 (EVEX byte 3, bit [6-5]—S₂₋₁) is interpreted as the round operationfield 2559A, while when the RL field 2557A contains a 0 (VSIZE 2557A.2)the rest of the beta field 2554 (EVEX byte 3, bit [6-5]—S₂₋₁) isinterpreted as the vector length field 2559B (EVEX byte 3, bit[6-5]—L₁₋₀). When U=1 and the MOD field 2642 contains 00, 01, or 10(signifying a memory access operation), the beta field 2554 (EVEX byte3, bits [6:4]—SSS) is interpreted as the vector length field 2559B (EVEXbyte 3, bit [6-5]—L₁₋₀) and the broadcast field 2557B (EVEX byte 3, bit[4]—B).

Exemplary Register Architecture

FIG. 27 is a block diagram of a register architecture 2700 according toone embodiment. In the embodiment illustrated, there are 32 vectorregisters 2710 that are 512 bits wide; these registers are referenced aszmm0 through zmm31. The lower order 256 bits of the lower 16 zmmregisters are overlaid on registers ymm0-16. The lower order 128 bits ofthe lower 16 zmm registers (the lower order 128 bits of the ymmregisters) are overlaid on registers xmm0-15. The specific vectorfriendly instruction format 2600 operates on these overlaid registerfile as illustrated in the below tables.

Adjustable Vector Length Class Operations Registers InstructionTemplates that A (FIG. 2510, 2515, zmm registers (the vector length is64 do not include the vector 25A; U = 0) 2525, 2530 byte) length field2559B B (FIG. 2512 zmm registers (the vector length is 64 25B; U = 1)byte) Instruction templates that B (FIG. 2517, 2527 zmm, ymm, or xmmregisters (the do include the vector 25B; U = 1) vector length is64-byte, 32 byte, or 16 length field 2559B byte) depending on the vectorlength field 2559B

In other words, the vector length field 2559B selects between a maximumlength and one or more other shorter lengths, where each such shorterlength is half the length of the preceding length; and instructionstemplates without the vector length field 2559B operate on the maximumvector length. Further, in one embodiment, the class B instructiontemplates of the specific vector friendly instruction format 2600operate on packed or scalar single/double-precision floating point dataand packed or scalar integer data. Scalar operations are operationsperformed on the lowest order data element position in a zmm/ymm/xmmregister; the higher order data element positions are either left thesame as they were prior to the instruction or zeroed depending on theembodiment.

Write mask registers 2715—in the embodiment illustrated, there are 8write mask registers (k0 through k7), each 64 bits in size. In analternate embodiment, the write mask registers 2715 are 16 bits in size.As previously described, in one embodiment, the vector mask register k0may not be used as a write mask; when the encoding that would normallyindicate k0 is used for a write mask, it selects a hardwired write maskof 0xFFFF, effectively disabling write masking for that instruction.

General-purpose registers 2725—in the embodiment illustrated, there aresixteen 64-bit general-purpose registers that are used along with theexisting x86 addressing modes to address memory operands. Theseregisters are referenced by the names RAX, RBX, RCX, RDX, RBP, RSI, RDI,RSP, and R8 through R15.

Scalar floating point stack register file (x87 stack) 2745, on which isaliased the MMX packed integer flat register file 2750—in the embodimentillustrated, the x87 stack is an eight-element stack used to performscalar floating-point operations on 32/64/80-bit floating point datausing the x87 instruction set extension; while the MMX registers areused to perform operations on 64-bit packed integer data, as well as tohold operands for some operations performed between the MMX and XMMregisters.

Alternative embodiments may use wider or narrower registers.Additionally, alternative embodiments may use more, less, or differentregister files and registers.

Exemplary Core Architectures, Processors, and Computer Architectures

Processor cores may be implemented in different ways, for differentpurposes, and in different processors. For instance, implementations ofsuch cores may include: 1) a general purpose in-order core intended forgeneral-purpose computing; 2) a high performance general purposeout-of-order core intended for general-purpose computing; 3) a specialpurpose core intended primarily for graphics and/or scientific(throughput) computing. Implementations of different processors mayinclude: 1) a CPU including one or more general purpose in-order coresintended for general-purpose computing and/or one or more generalpurpose out-of-order cores intended for general-purpose computing; and2) a coprocessor including one or more special purpose cores intendedprimarily for graphics and/or scientific (throughput). Such differentprocessors lead to different computer system architectures, which mayinclude: 1) the coprocessor on a separate chip from the CPU; 2) thecoprocessor on a separate die in the same package as a CPU; 3) thecoprocessor on the same die as a CPU (in which case, such a coprocessoris sometimes referred to as special purpose logic, such as integratedgraphics and/or scientific (throughput) logic, or as special purposecores); and 4) a system on a chip that may include on the same die thedescribed CPU (sometimes referred to as the application core(s) orapplication processor(s)), the above described coprocessor, andadditional functionality. Exemplary core architectures are describednext, followed by descriptions of exemplary processors and computerarchitectures.

Exemplary Core Architectures In-Order and Out-of-Order Core BlockDiagram

FIG. 28A is a block diagram illustrating both an exemplary in-orderpipeline and an exemplary register renaming, out-of-orderissue/execution pipeline according to embodiments. FIG. 28B is a blockdiagram illustrating both an exemplary embodiment of an in-orderarchitecture core and an exemplary register renaming, out-of-orderissue/execution architecture core to be included in a processoraccording to embodiments. The solid lined boxes in FIGS. 28A-Billustrate the in-order pipeline and in-order core, while the optionaladdition of the dashed lined boxes illustrates the register renaming,out-of-order issue/execution pipeline and core. Given that the in-orderaspect is a subset of the out-of-order aspect, the out-of-order aspectwill be described.

In FIG. 28A, a processor pipeline 2800 includes a fetch stage 2802, alength decode stage 2804, a decode stage 2806, an allocation stage 2808,a renaming stage 2810, a scheduling (also known as a dispatch or issue)stage 2812, a register read/memory read stage 2814, an execute stage2816, a write back/memory write stage 2818, an exception handling stage2822, and a commit stage 2824.

FIG. 28B shows processor core 2890 including a front-end unit 2830coupled to an execution engine unit 2850, and both are coupled to amemory unit 2870. The core 2890 may be a reduced instruction setcomputing (RISC) core, a complex instruction set computing (CISC) core,a very long instruction word (VLIW) core, or a hybrid or alternativecore type. As yet another option, the core 2890 may be a special-purposecore, such as, for example, a network or communication core, compressionengine, coprocessor core, general purpose computing graphics processingunit (GPGPU) core, graphics core, or the like.

The front-end unit 2830 includes a branch prediction unit 2832 coupledto an instruction cache unit 2834, which is coupled to an instructiontranslation lookaside buffer (TLB) 2836, which is coupled to aninstruction fetch unit 2838, which is coupled to a decode unit 2840. Thedecode unit 2840 (or decoder) may decode instructions, and generate asan output one or more micro-operations, micro-code entry points,microinstructions, other instructions, or other control signals, whichare decoded from, or which otherwise reflect, or are derived from, theoriginal instructions. The decode unit 2840 may be implemented usingvarious different mechanisms. Examples of suitable mechanisms include,but are not limited to, look-up tables, hardware implementations,programmable logic arrays (PLAs), microcode read only memories (ROMs),etc. In one embodiment, the core 2890 includes a microcode ROM or othermedium that stores microcode for certain macroinstructions (e.g., indecode unit 2840 or otherwise within the front-end unit 2830). Thedecode unit 2840 is coupled to a rename/allocator unit 2852 in theexecution engine unit 2850.

The execution engine unit 2850 includes the rename/allocator unit 2852coupled to a retirement unit 2854 and a set of one or more schedulerunit(s) 2856. The scheduler unit(s) 2856 represents any number ofdifferent schedulers, including reservations stations, centralinstruction window, etc. The scheduler unit(s) 2856 is coupled to thephysical register file(s) unit(s) 2858. Each of the physical registerfile(s) units 2858 represents one or more physical register files,different ones of which store one or more different data types, such asscalar integer, scalar floating point, packed integer, packed floatingpoint, vector integer, vector floating point, status (e.g., aninstruction pointer that is the address of the next instruction to beexecuted), etc. In one embodiment, the physical register file(s) unit2858 comprises a vector registers unit, a write mask registers unit, anda scalar registers unit. These register units may provide architecturalvector registers, vector mask registers, and general-purpose registers.The physical register file(s) unit(s) 2858 is overlapped by theretirement unit 2854 to illustrate various ways in which registerrenaming and out-of-order execution may be implemented (e.g., using areorder buffer(s) and a retirement register file(s); using a futurefile(s), a history buffer(s), and a retirement register file(s); using aregister maps and a pool of registers; etc.). The retirement unit 2854and the physical register file(s) unit(s) 2858 are coupled to theexecution cluster(s) 2860. The execution cluster(s) 2860 includes a setof one or more execution units 2862 and a set of one or more memoryaccess units 2864. The execution units 2862 may perform variousoperations (e.g., shifts, addition, subtraction, multiplication) and onvarious types of data (e.g., scalar floating point, packed integer,packed floating point, vector integer, vector floating point). Whilesome embodiments may include a number of execution units dedicated tospecific functions or sets of functions, other embodiments may includeonly one execution unit or multiple execution units that all perform allfunctions. The scheduler unit(s) 2856, physical register file(s) unit(s)2858, and execution cluster(s) 2860 are shown as being possibly pluralbecause certain embodiments create separate pipelines for certain typesof data/operations (e.g., a scalar integer pipeline, a scalar floatingpoint/packed integer/packed floating point/vector integer/vectorfloating point pipeline, and/or a memory access pipeline that each havetheir own scheduler unit, physical register file(s) unit, and/orexecution cluster—and in the case of a separate memory access pipeline,certain embodiments are implemented in which only the execution clusterof this pipeline has the memory access unit(s) 2864). It should also beunderstood that where separate pipelines are used, one or more of thesepipelines may be out-of-order issue/execution and the rest in-order.

The set of memory access units 2864 is coupled to the memory unit 2870,which includes a data TLB unit 2872 coupled to a data cache unit 2874coupled to a level 2 (L2) cache unit 2876. In one exemplary embodiment,the memory access units 2864 may include a load unit, a store addressunit, and a store data unit, each of which is coupled to the data TLBunit 2872 in the memory unit 2870. The instruction cache unit 2834 isfurther coupled to a level 2 (L2) cache unit 2876 in the memory unit2870. The L2 cache unit 2876 is coupled to one or more other levels ofcache and eventually to a main memory.

By way of example, the exemplary register renaming, out-of-orderissue/execution core architecture may implement the pipeline 2800 asfollows: 1) the instruction fetch 2838 performs the fetch and lengthdecoding stages 2802 and 2804; 2) the decode unit 2840 performs thedecode stage 2806; 3) the rename/allocator unit 2852 performs theallocation stage 2808 and renaming stage 2810; 4) the scheduler unit(s)2856 performs the schedule stage 2812; 5) the physical register file(s)unit(s) 2858 and the memory unit 2870 perform the register read/memoryread stage 2814; the execution cluster 2860 perform the execute stage2816; 6) the memory unit 2870 and the physical register file(s) unit(s)2858 perform the write back/memory write stage 2818; 7) various unitsmay be involved in the exception handling stage 2822; and 8) theretirement unit 2854 and the physical register file(s) unit(s) 2858perform the commit stage 2824.

The core 2890 may support one or more instructions sets (e.g., the x86instruction set (with some extensions that have been added with newerversions); the MIPS instruction set of MIPS Technologies of Sunnyvale,Calif.; the ARM instruction set (with optional additional extensionssuch as NEON) of ARM Holdings of Sunnyvale, Calif.), including theinstruction(s) described herein. In one embodiment, the core 2890includes logic to support a packed data instruction set extension (e.g.,AVX1, AVX2), thereby allowing the operations used by many multimediaapplications to be performed using packed data.

It should be understood that the core may support multithreading(executing two or more parallel sets of operations or threads), and maydo so in a variety of ways including time sliced multithreading,simultaneous multithreading (where a single physical core provides alogical core for each of the threads that physical core issimultaneously multithreading), or a combination thereof (e.g., timesliced fetching and decoding and simultaneous multithreading thereaftersuch as in the Intel® Hyperthreading technology).

While register renaming is described in the context of out-of-orderexecution, it should be understood that register renaming may be used inan in-order architecture. While the illustrated embodiment of theprocessor also includes separate instruction and data cache units2834/2874 and a shared L2 cache unit 2876, alternative embodiments mayhave a single internal cache for both instructions and data, such as,for example, a Level 1 (L1) internal cache, or multiple levels ofinternal cache. In some embodiments, the system may include acombination of an internal cache and an external cache that is externalto the core and/or the processor. Alternatively, all of the cache may beexternal to the core and/or the processor.

Specific Exemplary In-Order Core Architecture

FIGS. 29A-B illustrate a block diagram of a more specific exemplaryin-order core architecture, which core would be one of several logicblocks (including other cores of the same type and/or different types)in a chip. The logic blocks communicate through a high-bandwidthinterconnect network (e.g., a ring network) with some fixed functionlogic, memory I/O interfaces, and other necessary I/O logic, dependingon the application.

FIG. 29A is a block diagram of a single processor core, along with itsconnection to the on-die interconnect network 2902 and with its localsubset of the Level 2 (L2) cache 2904, according to embodiments. In oneembodiment, an instruction decoder 2900 supports the x86 instruction setwith a packed data instruction set extension. An L1 cache 2906 allowslow-latency accesses to cache memory into the scalar and vector units.While in one embodiment (to simplify the design), a scalar unit 2908 anda vector unit 2910 use separate register sets (respectively, scalarregisters 2912 and vector registers 2914) and data transferred betweenthem is written to memory and then read back in from a level 1 (L1)cache 2906, alternative embodiments may use a different approach (e.g.,use a single register set or include a communication path that allowdata to be transferred between the two register files without beingwritten and read back).

The local subset of the L2 cache 2904 is part of a global L2 cache thatis divided into separate local subsets, one per processor core. Eachprocessor core has a direct access path to its own local subset of theL2 cache 2904. Data read by a processor core is stored in its L2 cachesubset 2904 and may be accessed quickly, in parallel with otherprocessor cores accessing their own local L2 cache subsets. Data writtenby a processor core is stored in its own L2 cache subset 2904 and isflushed from other subsets, if necessary. The ring network ensurescoherency for shared data. The ring network is bi-directional to allowagents such as processor cores, L2 caches and other logic blocks tocommunicate with each other within the chip. Each ring data-path is1012-bits wide per direction.

FIG. 29B is an expanded view of part of the processor core in FIG. 29Aaccording to embodiments. FIG. 29B includes an L1 data cache 2906A partof the L1 cache 2904, as well as more detail regarding the vector unit2910 and the vector registers 2914. Specifically, the vector unit 2910is a 16-wide vector processing unit (VPU) (see the 16-wide ALU 2928),which executes one or more of integer, single-precision float, anddouble-precision float instructions. The VPU supports swizzling theregister inputs with swizzle unit 2920, numeric conversion with numericconvert units 2922A-B, and replication with replication unit 2924 on thememory input. Write mask registers 2926 allow predicating resultingvector writes.

FIG. 30 is a block diagram of a processor 3000 that may have more thanone core, may have an integrated memory controller, and may haveintegrated graphics according to embodiments. The solid lined boxes inFIG. 30 illustrate a processor 3000 with a single core 3002A, a systemagent 3010, a set of one or more bus controller units 3016, while theoptional addition of the dashed lined boxes illustrates an alternativeprocessor 3000 with multiple cores 3002A-N, a set of one or moreintegrated memory controller unit(s) 3014 in the system agent unit 3010,and special purpose logic 3008.

Thus, different implementations of the processor 3000 may include: 1) aCPU with the special purpose logic 3008 being integrated graphics and/orscientific (throughput) logic (which may include one or more cores), andthe cores 3002A-N being one or more general purpose cores (e.g., generalpurpose in-order cores, general purpose out-of-order cores, acombination of the two); 2) a coprocessor with the cores 3002A-N being alarge number of special purpose cores intended primarily for graphicsand/or scientific (throughput); and 3) a coprocessor with the cores3002A-N being a large number of general purpose in-order cores. Thus,the processor 3000 may be a general-purpose processor, coprocessor orspecial-purpose processor, such as, for example, a network orcommunication processor, compression engine, graphics processor, GPGPU(general purpose graphics processing unit), a high-throughput manyintegrated core (MIC) coprocessor (including 30 or more cores), embeddedprocessor, or the like. The processor may be implemented on one or morechips. The processor 3000 may be a part of and/or may be implemented onone or more substrates using any of a number of process technologies,such as, for example, BiCMOS, CMOS, or NMOS.

The memory hierarchy includes one or more levels of cache within thecores, a set or one or more shared cache units 3006, and external memory(not shown) coupled to the set of integrated memory controller units3014. The set of shared cache units 3006 may include one or moremid-level caches, such as level 2 (L2), level 3 (L3), level 4 (L4), orother levels of cache, a last level cache (LLC), and/or combinationsthereof. While in one embodiment a ring based interconnect unit 3012interconnects the special purpose logic 3008 (integrated graphics logicis an example of and is also referred to herein as special purposelogic), the set of shared cache units 3006, and the system agent unit3010/integrated memory controller unit(s) 3014, alternative embodimentsmay use any number of well-known techniques for interconnecting suchunits. In one embodiment, coherency is maintained between one or morecache units 3006 and cores 3002A-N.

In some embodiments, one or more of the cores 3002A-N are capable ofmultithreading. The system agent 3010 includes those componentscoordinating and operating cores 3002A-N. The system agent unit 3010 mayinclude for example a power control unit (PCU) and a display unit. ThePCU may be or include logic and components needed for regulating thepower state of the cores 3002A-N and the special purpose logic 3008. Thedisplay unit is for driving one or more externally connected displays.

The cores 3002A-N may be homogenous or heterogeneous in terms ofarchitecture instruction set; that is, two or more of the cores 3002A-Nmay be capable of execution the same instruction set, while others maybe capable of executing only a subset of that instruction set or adifferent instruction set.

Exemplary Computer Architectures

FIGS. 31-34 are block diagrams of exemplary computer architectures.Other system designs and configurations known in the arts for laptops,desktops, handheld PCs, personal digital assistants, engineeringworkstations, servers, network devices, network hubs, switches, embeddedprocessors, digital signal processors (DSPs), graphics devices, videogame devices, set-top boxes, micro controllers, cell phones, portablemedia players, hand held devices, and various other electronic devices,are also suitable. In general, a huge variety of systems or electronicdevices capable of incorporating a processor and/or other executionlogic as disclosed herein are generally suitable.

Referring now to FIG. 31, shown is a block diagram of a system 3100 inaccordance with one embodiment of the present invention. The system 3100may include one or more processors 3110, 3115, which are coupled to acontroller hub 3120. In one embodiment the controller hub 3120 includesa graphics memory controller hub (GMCH) 3190 and an Input/Output Hub(IOH) 3150 (which may be on separate chips); the GMCH 3190 includesmemory and graphics controllers to which are coupled memory 3140 and acoprocessor 3145; the IOH 3150 couples input/output (I/O) devices 3160to the GMCH 3190. Alternatively, one or both of the memory and graphicscontrollers are integrated within the processor (as described herein),the memory 3140 and the coprocessor 3145 are coupled directly to theprocessor 3110, and the controller hub 3120 in a single chip with theIOH 3150.

The optional nature of additional processors 3115 is denoted in FIG. 31with broken lines. Each processor 3110, 3115 may include one or more ofthe processing cores described herein and may be some version of theprocessor 3000.

The memory 3140 may be, for example, dynamic random-access memory(DRAM), phase change memory (PCM), or a combination of the two. For atleast one embodiment, the controller hub 3120 communicates with theprocessor(s) 3110, 3115 via a multi-drop bus, such as a frontside bus(FSB), point-to-point interface such as QuickPath Interconnect (QPI), orsimilar connection 3195.

In one embodiment, the coprocessor 3145 is a special-purpose processor,such as, for example, a high-throughput MIC processor, a network orcommunication processor, compression engine, graphics processor, GPGPU,embedded processor, or the like. In one embodiment, controller hub 3120may include an integrated graphics accelerator.

There may be a variety of differences between the physical resources3110, 3115 in terms of a spectrum of metrics of merit includingarchitectural, microarchitectural, thermal, power consumptioncharacteristics, and the like.

In one embodiment, the processor 3110 executes instructions that controldata processing operations of a general type. Embedded within theinstructions may be coprocessor instructions. The processor 3110recognizes these coprocessor instructions as being of a type that shouldbe executed by the attached coprocessor 3145. Accordingly, the processor3110 issues these coprocessor instructions (or control signalsrepresenting coprocessor instructions) on a coprocessor bus or otherinterconnect, to coprocessor 3145. Coprocessor(s) 3145 accept andexecute the received coprocessor instructions.

Referring now to FIG. 32, shown is a block diagram of a first morespecific exemplary system 3200 in accordance with an embodiment of thepresent invention. As shown in FIG. 32, multiprocessor system 3200 is apoint-to-point interconnect system, and includes a first processor 3270and a second processor 3280 coupled via a point-to-point interconnect3250. Each of processors 3270 and 3280 may be some version of theprocessor 3000. In one embodiment, processors 3270 and 3280 arerespectively processors 3110 and 3115, while coprocessor 3238 iscoprocessor 3145. In another embodiment, processors 3270 and 3280 arerespectively processor 3110 coprocessor 3145.

Processors 3270 and 3280 are shown including integrated memorycontroller (IMC) units 3272 and 3282, respectively. Processor 3270 alsoincludes as part of its bus controller unit's point-to-point (P-P)interfaces 3276 and 3278; similarly, second processor 3280 includes P-Pinterfaces 3286 and 3288. Processors 3270, 3280 may exchange informationvia a point-to-point (P-P) interface 3250 using P-P interface circuits3278, 3288. As shown in FIG. 32, IMCs 3272 and 3282 couple theprocessors to respective memories, namely a memory 3232 and a memory3234, which may be portions of main memory locally attached to therespective processors.

Processors 3270, 3280 may each exchange information with a chipset 3290via individual P-P interfaces 3252, 3254 using point to point interfacecircuits 3276, 3294, 3286, 3298. Chipset 3290 may optionally exchangeinformation with the coprocessor 3238 via a high-performance interface3292. In one embodiment, the coprocessor 3238 is a special-purposeprocessor, such as, for example, a high-throughput MIC processor, anetwork or communication processor, compression engine, graphicsprocessor, GPGPU, embedded processor, or the like.

A shared cache (not shown) may be included in either processor oroutside of both processors yet connected with the processors via P-Pinterconnect, such that either or both processors' local cacheinformation may be stored in the shared cache if a processor is placedinto a low power mode.

Chipset 3290 may be coupled to a first bus 3216 via an interface 3296.In one embodiment, first bus 3216 may be a Peripheral ComponentInterconnect (PCI) bus, or a bus such as a PCI Express bus or anotherthird generation I/O interconnect bus, although the scope of the presentinvention is not so limited.

As shown in FIG. 32, various I/O devices 3214 may be coupled to firstbus 3216, along with a bus bridge 3218 which couples first bus 3216 to asecond bus 3220. In one embodiment, one or more additional processor(s)3215, such as coprocessors, high-throughput MIC processors, GPGPU's,accelerators (such as, e.g., graphics accelerators or digital signalprocessing (DSP) units), field programmable gate arrays, or any otherprocessor, are coupled to first bus 3216. In one embodiment, second bus3220 may be a low pin count (LPC) bus. Various devices may be coupled toa second bus 3220 including, for example, a keyboard and/or mouse 3222,communication devices 3227 and a storage unit 3228 such as a disk driveor other mass storage device which may include instructions/code anddata 3230, in one embodiment. Further, an audio I/O 3224 may be coupledto the second bus 3220. Note that other architectures are possible. Forexample, instead of the point-to-point architecture of FIG. 32, a systemmay implement a multi-drop bus or other such architecture.

Referring now to FIG. 33, shown is a block diagram of a second morespecific exemplary system 3300 in accordance with an embodiment of thepresent invention. Like elements in FIGS. 32 and 33 bear like referencenumerals, and certain aspects of FIG. 32 have been omitted from FIG. 33in order to avoid obscuring other aspects of FIG. 33.

FIG. 33 illustrates that the processors 3270, 3280 may includeintegrated memory and I/O control logic (“CL”) 3372 and 3382,respectively. Thus, the CL 3372, 3382 include integrated memorycontroller units and include I/O control logic. FIG. 33 illustrates thatnot only are the memories 3232, 3234 coupled to the CL 3372, 3382, butalso that I/O devices 3314 are also coupled to the control logic 3372,3382. Legacy I/O devices 3315 are coupled to the chipset 3290.

Referring now to FIG. 34, shown is a block diagram of a SoC 3400 inaccordance with an embodiment of the present invention. Similar elementsin FIG. 30 bear like reference numerals. Also, dashed lined boxes areoptional features on more advanced SoCs. In FIG. 34, an interconnectunit(s) 3402 is coupled to: an application processor 3410 which includesa set of one or more cores 3002A-N, which include cache units 3004A-N,and shared cache unit(s) 3006; a system agent unit 3010; a buscontroller unit(s) 3016; an integrated memory controller unit(s) 3014; aset or one or more coprocessors 3420 which may include integratedgraphics logic, an image processor, an audio processor, and a videoprocessor; an static random access memory (SRAM) unit 3430; a directmemory access (DMA) unit 3432; and a display unit 3440 for coupling toone or more external displays. In one embodiment, the coprocessor(s)3420 include a special-purpose processor, such as, for example, anetwork or communication processor, compression engine, GPGPU, ahigh-throughput MIC processor, embedded processor, or the like.

Embodiments of the mechanisms disclosed herein may be implemented inhardware, software, firmware, or a combination of such implementationapproaches. Embodiments may be implemented as computer programs orprogram code executing on programmable systems comprising at least oneprocessor, a storage system (including volatile and non-volatile memoryand/or storage elements), at least one input device, and at least oneoutput device.

Program code, such as code 3230 illustrated in FIG. 32, may be appliedto input instructions to perform the functions described herein andgenerate output information. The output information may be applied toone or more output devices, in known fashion. For purposes of thisapplication, a processing system includes any system that has aprocessor, such as, for example; a digital signal processor (DSP), amicrocontroller, an application specific integrated circuit (ASIC), or amicroprocessor.

The program code may be implemented in a high-level procedural orobject-oriented programming language to communicate with a processingsystem. The program code may also be implemented in assembly or machinelanguage, if desired. In fact, the mechanisms described herein are notlimited in scope to any particular programming language. In any case,the language may be a compiled or interpreted language.

One or more aspects of at least one embodiment may be implemented byrepresentative instructions stored on a machine-readable medium whichrepresents various logic within the processor, which when read by amachine causes the machine to fabricate logic to perform the techniquesdescribed herein. Such representations, known as “IP cores,” may bestored on a tangible, machine readable medium and supplied to variouscustomers or manufacturing facilities to load into the fabricationmachines that actually make the logic or processor.

Such machine-readable storage media may include, without limitation,non-transitory, tangible arrangements of articles manufactured or formedby a machine or device, including storage media such as hard disks, anyother type of disk including floppy disks, optical disks, compact diskread-only memories (CD-ROMs), compact disk rewritables (CD-RWs), andmagneto-optical disks, semiconductor devices such as read-only memories(ROMs), random access memories (RAMs) such as dynamic random accessmemories (DRAMs), static random access memories (SRAMs), erasableprogrammable read-only memories (EPROMs), flash memories, electricallyerasable programmable read-only memories (EEPROMs), phase change memory(PCM), magnetic or optical cards, or any other type of media suitablefor storing electronic instructions.

Accordingly, embodiments also include non-transitory, tangiblemachine-readable media containing instructions or containing designdata, such as Hardware Description Language (HDL), which definesstructures, circuits, apparatuses, processors and/or system featuresdescribed herein. Such embodiments may also be referred to as programproducts.

Emulation (Including Binary Translation, Code Morphing, Etc.)

In some cases, an instruction converter may be used to convert aninstruction from a source instruction set to a target instruction set.For example, the instruction converter may translate (e.g., using staticbinary translation, dynamic binary translation including dynamiccompilation), morph, emulate, or otherwise convert an instruction to oneor more other instructions to be processed by the core. The instructionconverter may be implemented in software, hardware, firmware, or acombination thereof. The instruction converter may be on processor, offprocessor, or part on and part off processor.

FIG. 35 is a block diagram contrasting the use of a software instructionconverter to convert binary instructions in a source instruction set tobinary instructions in a target instruction set according toembodiments. In the illustrated embodiment, the instruction converter isa software instruction converter, although alternatively the instructionconverter may be implemented in software, firmware, hardware, or variouscombinations thereof. FIG. 35 shows a program in a high-level language3502 may be compiled using an x86 compiler 3504 to generate x86 binarycode 3506 that may be natively executed by a processor with at least onex86 instruction set core 3516. The processor with at least one x86instruction set core 3516 represents any processor that may performsubstantially the same functions as an Intel processor with at least onex86 instruction set core by compatibly executing or otherwise processing(1) a substantial portion of the instruction set of the Intel x86instruction set core or (2) object code versions of applications orother software targeted to run on an Intel processor with at least onex86 instruction set core, in order to achieve substantially the sameresult as an Intel processor with at least one x86 instruction set core.The x86 compiler 3504 represents a compiler that is operable to generatex86 binary code 3506 (e.g., object code) that may, with or withoutadditional linkage processing, be executed on the processor with atleast one x86 instruction set core 3516. Similarly, FIG. 35 shows theprogram in the high level language 3502 may be compiled using analternative instruction set compiler 3508 to generate alternativeinstruction set binary code 3510 that may be natively executed by aprocessor without at least one x86 instruction set core 3514 (e.g., aprocessor with cores that execute the MIPS instruction set of MIPSTechnologies of Sunnyvale, Calif. and/or that execute the ARMinstruction set of ARM Holdings of Sunnyvale, Calif.). The instructionconverter 3512 is used to convert the x86 binary code 3506 into codethat may be natively executed by the processor without an x86instruction set core 3514. This converted code is not likely to be thesame as the alternative instruction set binary code 3510 because aninstruction converter capable of this is difficult to make; however, theconverted code will accomplish the general operation and be made up ofinstructions from the alternative instruction set. Thus, the instructionconverter 3512 represents software, firmware, hardware, or a combinationthereof that, through emulation, simulation or any other process, allowsa processor or other electronic device that does not have an x86instruction set processor or core to execute the x86 binary code 3506.

What is claimed is:
 1. A processor comprising: storage for a matrix; adecoder to decode an instruction having a format including an opcodefield to specify an opcode and a first operand field to specify a set ofirregularly spaced memory locations; and execution circuitry to, inresponse to the decoded instruction, calculate a set of addressescorresponding to the set of irregularly spaced memory locations andtransfer a set of rows of data between the storage and the set ofirregularly spaced memory locations.
 2. The processor of claim 1,wherein the first operand field is to specify the set of irregularlyspaced memory locations by specifying a set of indices.
 3. The processorof claim 2, wherein the first operand field is to specify the set ofindices by specifying a register to store an address of a first index inthe set of indices.
 4. The processor of claim 2, wherein the executioncircuitry is to calculate the set of addresses by adding each of the setof indices to a beginning memory address.
 5. The processor of claim 4,wherein the first operand field is also to specify the beginning addressor a base address with which the execution circuitry is to calculate thebeginning address.
 6. The processor of claim 1, wherein the format isalso to include a second operand field to specify a register as thestorage for the matrix.
 7. The processor of claim 1, wherein theinstruction is a row gather instruction and the execution circuitry, inresponse to the instruction, is to load the set of rows of data to thestorage from the set of irregularly spaced memory locations.
 8. Theprocessor of claim 1, wherein the instruction is a row scatterinstruction and the execution circuitry, in response to the instruction,is to store the set of rows of data from the storage to the set ofirregularly spaced memory locations.
 9. A method comprising: decoding aninstruction having a format including an opcode field to specify anopcode and a first operand field to specify a set of irregularly spacedmemory locations; and executing the decoded instruction, whereinexecuting includes calculating a set of addresses corresponding to theset of irregularly spaced memory locations and transferring a set ofrows of data between storage for a matrix and the set of irregularlyspaced memory locations.
 10. The method of claim 9, wherein the firstoperand field is to specify the set of irregularly spaced memorylocations by specifying a set of indices.
 11. The method of claim 10,wherein calculating the set of addresses includes adding each of the setof indices to a beginning memory address.
 12. The method of claim 9,wherein the format is also to include a second operand field to specifya register as the storage for the matrix.
 13. The method of claim 9,wherein the instruction is a row gather instruction and executingincludes loading the rows of data to the storage from the set ofirregularly spaced memory locations.
 14. The method of claim 9, whereinthe instruction is a row scatter instruction and executing includesstoring the rows of data from the storage to the set of irregularlyspaced memory locations.
 15. A non-transitory machine-readable mediumcontaining instructions, when executed by a processor, to cause theprocessor to respond by: decoding an instruction having a formatincluding an opcode field to specify an opcode and a first operand fieldto specify a set of irregularly spaced memory locations; and executingthe decoded instruction, wherein executing includes calculating a set ofaddresses corresponding to the set of irregularly spaced memorylocations and transferring a set of rows of data between storage for amatrix and the set of irregularly spaced memory locations.
 16. Thenon-transitory machine-readable medium of claim 15, wherein the firstoperand field is to specify the set of irregularly spaced memorylocations by specifying a set of indices.
 17. The non-transitorymachine-readable medium of claim 16, wherein calculating the set ofaddresses includes adding each of the set of indices to a beginningmemory address.
 18. The non-transitory machine-readable medium of claim15, wherein the format is also to include a second operand field tospecify a register as the storage for the matrix.
 19. The non-transitorymachine-readable medium of claim 15, wherein the instruction is a rowgather instruction and executing includes loading the set of rows ofdata to the storage from the set of irregularly spaced memory locations.20. The non-transitory machine-readable medium of claim 15, wherein theinstruction is a row scatter instruction and executing includes storingthe set of rows of data from the storage to the set of irregularlyspaced memory locations.